The influenza pandemic of 1918, known as the Spanish Flu, was one of the deadliest and widespread pandemics in human history. The scale of the outbreak, as well as limitations in technology, medicine and communication, create difficulties when trying to uncover accurate figures relating to the pandemic. Estimates suggest that the virus, known as the H1N1 influenza virus, infected more than one quarter of the global population, which equated to approximately 500 million people in 1920. It was responsible for roughly 25 million fatalities, although some projections suggest that it could have caused double this number of deaths. The exact origins of this strain of influenza remain unclear to this day, however it was first noticed in Western Europe in the latter stages of the First World War. Wartime censorship in Europe meant that the severity of the pandemic was under-reported, while news outlets in neutral Spain were free to report openly about the impact of the virus; this gave the illusion that the virus was particularly strong in Spain, giving way to the term "Spanish Flu".

Effects of the virus

By late summer 1918, the pandemic had spread across the entire continent, and the H1N1 virus had mutated into a deadlier strain that weakened the infected's immune system more than traditional influenzas. Some studies suggest that, in contrast to these traditional influenza viruses, having a stronger immune system was actually a liability in the case of the H1N1 virus as it triggered what is known as a "cytokine storm". This is where white blood cells release proteins called cytokines, which signal the body to attack the virus, in turn releasing more white blood cells which release more cytokines. This cycle over-works and greatly weakens the immune system, often giving way to other infections; most commonly pneumonia in the case of the Spanish Flu. For this reason, the Spanish Flu had an uncommonly high fatality rate among young adults, who are traditionally the healthiest group in society. Some theories for the disproportionate death-rate among young adults suggest that the elderly's immune systems benefitted from exposure to earlier influenza pandemics, such as the "Asiatic/Russian Flu" pandemic of 1889.

Decrease in life expectancy As the war in Europe came to an end, soldiers returning home brought the disease to all corners of the world, and the pandemic reached global proportions. Isolated and under-developed nations were especially vulnerable; particularly in Samoa, where almost one quarter of the population died within two months and life expectancy fell to just barely over one year for those born in 1918; this was due to the arrival of a passenger ship from New Zealand in November 1918, where the infected passengers were not quarantined on board, allowing the disease to spread rapidly. Other areas where life expectancy dropped below ten years for those born in 1918 were present-day Afghanistan, the Congo, Fiji, Guatemala, Kenya, Micronesia, Serbia, Tonga and Uganda. The British Raj, now Bangladesh, India and Pakistan, saw more fatalities than any other region, with as many as five percent of the entire population perishing as a result of the pandemic. The pandemic also had a high fatality rate among pregnant women and infants, and greatly impacted infant mortality rates across the world. There were several waves of the pandemic until late 1920, although they decreased in severity as time progressed, and none were as fatal as the outbreak in 1918. A new strain of the H1N1 influenza virus did re-emerge in 2009, and was colloquially known as "Swine Flu"; thankfully it had a much lower fatality rate due to medical advancements across the twentieth century.

In the past four centuries, the population of the United States has grown from a recorded 350 people around the Jamestown colony of Virginia in 1610, to an estimated 331 million people in 2020. The pre-colonization populations of the indigenous peoples of the Americas have proven difficult for historians to estimate, as their numbers decreased rapidly following the introduction of European diseases (namely smallpox, plague and influenza). Native Americans were also omitted from most censuses conducted before the twentieth century, therefore the actual population of what we now know as the United States would have been much higher than the official census data from before 1800, but it is unclear by how much. Population growth in the colonies throughout the eighteenth century has primarily been attributed to migration from the British Isles and the Transatlantic slave trade; however it is also difficult to assert the ethnic-makeup of the population in these years as accurate migration records were not kept until after the 1820s, at which point the importation of slaves had also been illegalized. Nineteenth century In the year 1800, it is estimated that the population across the present-day United States was around six million people, with the population in the 16 admitted states numbering at 5.3 million. Migration to the United States began to happen on a large scale in the mid-nineteenth century, with the first major waves coming from Ireland, Britain and Germany. In some aspects, this wave of mass migration balanced out the demographic impacts of the American Civil War, which was the deadliest war in U.S. history with approximately 620 thousand fatalities between 1861 and 1865. The civil war also resulted in the emancipation of around four million slaves across the south; many of whose ancestors would take part in the Great Northern Migration in the early 1900s, which saw around six million black Americans migrate away from the south in one of the largest demographic shifts in U.S. history. By the end of the nineteenth century, improvements in transport technology and increasing economic opportunities saw migration to the United States increase further, particularly from southern and Eastern Europe, and in the first decade of the 1900s the number of migrants to the U.S. exceeded one million people in some years. Twentieth and twenty-first century The U.S. population has grown steadily throughout the past 120 years, reaching one hundred million in the 1910s, two hundred million in the 1960s, and three hundred million in 2007. In the past century, the U.S. established itself as a global superpower, with the world's largest economy (by nominal GDP) and most powerful military. Involvement in foreign wars has resulted in over 620,000 further U.S. fatalities since the Civil War, and migration fell drastically during the World Wars and Great Depression; however the population continuously grew in these years as the total fertility rate remained above two births per woman, and life expectancy increased (except during the Spanish Flu pandemic of 1918).

Since the Second World War, Latin America has replaced Europe as the most common point of origin for migrants, with Hispanic populations growing rapidly across the south and border states. Because of this, the proportion of non-Hispanic whites, which has been the most dominant ethnicity in the U.S. since records began, has dropped more rapidly in recent decades. Ethnic minorities also have a much higher birth rate than non-Hispanic whites, further contributing to this decline, and the share of non-Hispanic whites is expected to fall below fifty percent of the U.S. population by the mid-2000s. In 2020, the United States has the third-largest population in the world (after China and India), and the population is expected to reach four hundred million in the 2050s.

A key question in ecology is the relative impact of internal nonlinear dynamics and external perturbations on the long-term trajectories of natural systems. Measles has been analyzed extensively as a paradigm for consumer-resource dynamics due to the oscillatory nature of the host-pathogen life cycle, the abundance of rich data to test theory, and public health relevance. The dynamics of measles in London, in particular, has acted as a prototypical test bed for such analysis using incidence data from the pre-vaccination era (1944–1967). However, during this timeframe there were few external large-scale perturbations, limiting an assessment of the relative impact of internal and extra demographic perturbations to the host population. Here, we extended the previous London analyses to include nearly a century of data that also contains four major demographic changes: the First and Second World Wars, the 1918 influenza pandemic, and the start of a measles mass vaccination program. By combining mortality and incidence data using particle filtering methods, we show that a simple stochastic epidemic model, with minimal historical specifications, can capture the nearly 100 years of dynamics including changes caused by each of the major perturbations. We show that the majority of dynamic changes are explainable by the internal nonlinear dynamics of the system, tuned by demographic changes. In addition, the 1918 influenza pandemic and World War II acted as extra perturbations to this basic epidemic oscillator. Our analysis underlines that long-term ecological and epidemiological dynamics can follow very simple rules, even in a non-stationary population subject to significant perturbations and major secular changes.

In 1800, the region of Germany was not a single, unified nation, but a collection of decentralized, independent states, bound together as part of the Holy Roman Empire. This empire was dissolved, however, in 1806, during the Revolutionary and Napoleonic eras in Europe, and the German Confederation was established in 1815. Napoleonic reforms led to the abolition of serfdom, extension of voting rights to property-owners, and an overall increase in living standards. The population grew throughout the remainder of the century, as improvements in sanitation and medicine (namely, mandatory vaccination policies) saw child mortality rates fall in later decades. As Germany industrialized and the economy grew, so too did the argument for nationhood; calls for pan-Germanism (the unification of all German-speaking lands) grew more popular among the lower classes in the mid-1800s, especially following the revolutions of 1948-49. In contrast, industrialization and poor harvests also saw high unemployment in rural regions, which led to waves of mass migration, particularly to the U.S.. In 1886, the Austro-Prussian War united northern Germany under a new Confederation, while the remaining German states (excluding Austria and Switzerland) joined following the Franco-Prussian War in 1871; this established the German Empire, under the Prussian leadership of Emperor Wilhelm I and Chancellor Otto von Bismarck. 1871 to 1945 - Unification to the Second World War The first decades of unification saw Germany rise to become one of Europe's strongest and most advanced nations, and challenge other world powers on an international scale, establishing colonies in Africa and the Pacific. These endeavors were cut short, however, when the Austro-Hungarian heir apparent was assassinated in Sarajevo; Germany promised a "blank check" of support for Austria's retaliation, who subsequently declared war on Serbia and set the First World War in motion. Viewed as the strongest of the Central Powers, Germany mobilized over 11 million men throughout the war, and its army fought in all theaters. As the war progressed, both the military and civilian populations grew increasingly weakened due to malnutrition, as Germany's resources became stretched. By the war's end in 1918, Germany suffered over 2 million civilian and military deaths due to conflict, and several hundred thousand more during the accompanying influenza pandemic. Mass displacement and the restructuring of Europe's borders through the Treaty of Versailles saw the population drop by several million more.

Reparations and economic mismanagement also financially crippled Germany and led to bitter indignation among many Germans in the interwar period; something that was exploited by Adolf Hitler on his rise to power. Reckless printing of money caused hyperinflation in 1923, when the currency became so worthless that basic items were priced at trillions of Marks; the introduction of the Rentenmark then stabilized the economy before the Great Depression of 1929 sent it back into dramatic decline. When Hitler became Chancellor of Germany in 1933, the Nazi government disregarded the Treaty of Versailles' restrictions and Germany rose once more to become an emerging superpower. Hitler's desire for territorial expansion into eastern Europe and the creation of an ethnically-homogenous German empire then led to the invasion of Poland in 1939, which is considered the beginning of the Second World War in Europe. Again, almost every aspect of German life contributed to the war effort, and more than 13 million men were mobilized. After six years of war, and over seven million German deaths, the Axis powers were defeated and Germany was divided into four zones administered by France, the Soviet Union, the UK, and the U.S.. Mass displacement, shifting borders, and the relocation of peoples based on ethnicity also greatly affected the population during this time. 1945 to 2020 - Partition and Reunification In the late 1940s, cold war tensions led to two distinct states emerging in Germany; the Soviet-controlled east became the communist German Democratic Republic (DDR), and the three western zones merged to form the democratic Federal Republic of Germany. Additionally, Berlin was split in a similar fashion, although its location deep inside DDR territory created series of problems and opportunities for the those on either side. Life quickly changed depending on which side of the border one lived. Within a decade, rapid economic recovery saw West Germany become western Europe's strongest economy and a key international player. In the east, living standards were much lower, although unemployment was almost non-existent; internationally, East Germany was the strongest economy in the Eastern Bloc (after the USSR), though it eventually fell behind the West by the 1970s. The restriction of movement between the two states also led to labor shortages in the West, and an influx of migrants from...

In 2023, the population of the United Kingdom reached 68.3 million, compared with 67.6 million in 2022. The UK population has more than doubled since 1871 when just under 31.5 million lived in the UK and has grown by around 8.2 million since the start of the twenty-first century. For most of the twentieth century, the UK population steadily increased, with two noticeable drops in population occurring during World War One (1914-1918) and in World War Two (1939-1945). Demographic trends in postwar Britain After World War Two, Britain and many other countries in the Western world experienced a 'baby boom,' with a postwar peak of 1.02 million live births in 1947. Although the number of births fell between 1948 and 1955, they increased again between the mid-1950s and mid-1960s, with more than one million people born in 1964. Since 1964, however, the UK birth rate has fallen from 18.8 births per 1,000 people to a low of just 10.2 in 2020. As a result, the UK population has gotten significantly older, with the country's median age increasing from 37.9 years in 2001 to 40.7 years in 2022. What are the most populated areas of the UK? The vast majority of people in the UK live in England, which had a population of 57.7 million people in 2023. By comparison, Scotland, Wales, and Northern Ireland had populations of 5.44 million, 3.13 million, and 1.9 million, respectively. Within England, South East England had the largest population, at over 9.38 million, followed by the UK's vast capital city of London, at 8.8 million. London is far larger than any other UK city in terms of urban agglomeration, with just four other cities; Manchester, Birmingham, Leeds, and Glasgow, boasting populations that exceed one million people.

The pandemic influenza virus (2009 H1N1) was recently introduced into the human population. The hemagglutinin (HA) gene of 2009 H1N1 is derived from “classical swine H1N1” virus, which likely shares a common ancestor with the human H1N1 virus that caused the pandemic in 1918, whose descendant viruses are still circulating in the human population with highly altered antigenicity of HA. However, information on the structural basis to compare the HA antigenicity among 2009 H1N1, the 1918 pandemic, and seasonal human H1N1 viruses has been lacking. By homology modeling of the HA structure, here we show that HAs of 2009 H1N1 and the 1918 pandemic virus share a significant number of amino acid residues in known antigenic sites, suggesting the existence of common epitopes for neutralizing antibodies cross-reactive to both HAs. It was noted that the early human H1N1 viruses isolated in the 1930s–1940s still harbored some of the original epitopes that are also found in 2009 H1N1. Interestingly, while 2009 H1N1 HA lacks the multiple N-glycosylations that have been found to be associated with an antigenic change of the human H1N1 virus during the early epidemic of this virus, 2009 H1N1 HA still retains unique three-codon motifs, some of which became N-glycosylation sites via a single nucleotide mutation in the human H1N1 virus. We thus hypothesize that the 2009 H1N1 HA antigenic sites involving the conserved amino acids will soon be targeted by antibody-mediated selection pressure in humans. Indeed, amino acid substitutions predicted here are occurring in the recent 2009 H1N1 variants. The present study suggests that antibodies elicited by natural infection with the 1918 pandemic or its early descendant viruses play a role in specific immunity against 2009 H1N1, and provides an insight into future likely antigenic changes in the evolutionary process of 2009 H1N1 in the human population.

The First World War saw the mobilization of more than 65 million soldiers, and the deaths of almost 15 million soldiers and civilians combined. Approximately 8.8 million of these deaths were of military personnel, while six million civilians died as a direct result of the war; mostly through hunger, disease and genocide. The German army suffered the highest number of military losses, totaling at more than two million men. Turkey had the highest civilian death count, largely due to the mass extermination of Armenians, as well as Greeks and Assyrians. Varying estimates suggest that Russia may have suffered the highest number of military and total fatalities in the First World War. However, this is complicated by the subsequent Russian Civil War and Russia's total specific to the First World War remains unclear to this day.

Proportional deaths In 1914, Central and Eastern Europe was largely divided between the empires of Austria-Hungary, Germany and Russia, while the smaller Balkan states had only emerged in prior decades with the decline of the Ottoman Empire. For these reasons, the major powers in the east were able to mobilize millions of men from across their territories, as Britain and France did with their own overseas colonies, and were able to utilize their superior manpower to rotate and replace soldiers, whereas smaller nations did not have this luxury. For example, total military losses for Romania and Serbia are around 12 percent of Germany's total military losses; however, as a share of their total mobilized forces these countries lost roughly 33 percent of their armies, compared to Germany's 15 percent mortality rate. The average mortality rate of all deployed soldiers in the war was around 14 percent.

Unclarity in the totals Despite ending over a century ago, the total number of deaths resulting from the First World War remains unclear. The impact of the Influenza pandemic of 1918, as well as various classifications of when or why fatalities occurred, has resulted in varying totals with differences ranging in the millions. Parallel conflicts, particularly the Russian Civil War, have also made it extremely difficult to define which conflicts the fatalities should be attributed to. Since 2012, the totals given by Hirschfeld et al in Brill's Encyclopedia of the First World War have been viewed by many in the historical community as the most reliable figures on the subject.

In 1800, the population of Spain was approximately 14.7 million. This figure would rise consistently throughout the 19th century, and early 20th century. The population growth rate was set to increase in the mid-1900s, but this was interrupted by the Spanish Civil War, which would claim around half a million lives between 1936 and 1939. In spite of the war, the Spanish population continued to grow throughout these years, and reached 28 million by the middle of the century. Between the 1950s and 1970s, Spain observed a significant increase in its population growth, facilitated by the baby boom that followed the Second World War (as in most of Western Europe) as well as general medical improvements and increased life expectancy.

Beginning in the 1980s, Spain would begin a demographic transition marked by a dramatic drop in the fertility rate of the country, resulting in the population only growing by two million between the mid-1980s and 2000 (compared to an increase of two million every five or six years beforehand). There was a sharp rise in Spain’s population from 2000 to 2008, as strong economic growth would be accompanied by a dramatic surge in immigration to the country. This would plateau at just over 46 million in 2008 however, as the Great Recession took its toll on the country’s economy, and in 2020, Spain is estimated to have a population of approximately 46.8 million, which is the sixth-largest in Europe.

Abstract

The 2012-13 Pakistan Demographic and Health Survey was undertaken to provide current and reliable data on fertility and family planning, childhood mortality, maternal and child health, women’s and children’s nutritional status, women’s empowerment, domestic violence, and knowledge of HIV/AIDS. The survey was designed with the broad objective of providing policymakers with information to monitor and evaluate programmatic interventions based on empirical evidence.

The specific objectives of the survey are to: • collect high-quality data on topics such as fertility levels and preferences, contraceptive use, maternal and child health, infant (and especially neonatal) mortality levels, awareness regarding HIV/AIDS, and other indicators related to the Millennium Development Goals and the country’s Poverty Reduction Strategy Paper • investigate factors that affect maternal and neonatal morbidity and mortality (i.e., antenatal, delivery, and postnatal care) • provide information to address the evaluation needs of health and family planning programs for evidence-based planning • provide guidelines to program managers and policymakers that will allow them to effectively plan and implement future interventions

Geographic coverage

National coverage

Analysis unit

• Household
• Ever married women age 15-49
• Ever married men age 15-49

Kind of data

Sample survey data [ssd]

Sampling procedure

Sample Design The primary objective of the 2012-13 PDHS is to provide reliable estimates of key fertility, family planning, maternal, and child health indicators at the national, provincial, and urban and rural levels. NIPS coordinated the design and selection of the sample with the Pakistan Bureau of Statistics. The sample for the 2012-13 PDHS represents the population of Pakistan excluding Azad Jammu and Kashmir, FATA, and restricted military and protected areas. The universe consists of all urban and rural areas of the four provinces of Pakistan and Gilgit Baltistan, defined as such in the 1998 Population Census. PBS developed the urban area frame. All urban cities and towns are divided into mutually exclusive, small areas, known as enumeration blocks, that were identifiable with maps. Each enumeration block consists of about 200 to 250 households on average, and blocks are further grouped into low-, middle-, and high-income categories. The urban area sampling frame consists of 26,543 enumeration blocks, updated through the economic census conducted in 2003. In rural areas, lists of villages/mouzas/dehs developed through the 1998 population census were used as the sample frame. In this frame, each village/mouza/deh is identifiable by its name. In Balochistan, Islamabad, and Gilgit Baltistan, urban areas were oversampled and proportions were adjusted by applying sampling weights during the analysis.

A sample size of 14,000 households was estimated to provide reasonable precision for the survey indicators. NIPS trained 43 PBS staff members to obtain fresh listings from 248 urban and 252 rural survey sample areas across the country. The household listing was carried out from August to December 2012.

The second stage of sampling involved selecting households. At each sampling point, 28 households were selected by applying a systematic sampling technique with a random start. This resulted in 14,000 households being selected (6,944 in urban areas and 7,056 in rural areas). The survey was carried out in a total of 498 areas. Two areas of Balochistan province (Punjgur and Dera Bugti) were dropped because of their deteriorating law and order situations. Overall, 24 areas (mostly in Balochistan) were replaced, mainly because of their adverse law and order situation.

Refer to Appendix B in the final report for details of sample design and implementation.

Mode of data collection

Face-to-face [f2f]

Research instrument

The 2012-13 PDHS used four types of questionnaires: Household Questionnaire, Woman’s Questionnaire, Man’s Questionnaire, and Community Questionnaire. The contents of the Household, Woman’s, and Man’s Questionnaires were based on model questionnaires developed by the MEASURE DHS program. However, the questionnaires were modified, in consultation with a broad spectrum of research institutions, government departments, and local and international organizations, to reflect issues relevant to the Pakistani population, including migration status, family planning, domestic violence, HIV/AIDS, and maternal and child health. A series of questionnaire design meetings were organized by NIPS, and discussions from these meetings were used to finalize the survey questionnaires. The questionnaires were then translated into Urdu and Sindhi and pretested, after which they were further refined. The questionnaires were presented to the Technical Advisory Committee for final approval.

The Household Questionnaire was used to list the usual members and visitors in the selected households. Basic information was collected on the characteristics of each person listed, including age, sex, marital status, education, and relationship to the head of the household. Data on current school attendance, migration status, and survivorship of parents among those under age 18 were also collected. The questionnaire also provided the opportunity to identify ever-married women and men age 15-49 who were eligible for individual interviews and children age 0-5 eligible for anthropometry measurements. The Household Questionnaire collected information on characteristics of the dwelling unit as well, such as the source of drinking water; type of toilet facilities; type of cooking fuel; materials used for the floor, roof, and walls of the house; and ownership of durable goods, agricultural land, livestock/farm animals/poultry, and mosquito nets.

The Woman’s Questionnaire was used to collect information from ever-married women age 15-49 on the following topics: • Background characteristics (education, literacy, native tongue, marital status, etc.) • Reproductive history • Knowledge and use of family planning methods • Fertility preferences • Antenatal, delivery, and postnatal care • Breastfeeding and infant feeding practices • Vaccinations and childhood illnesses • Woman’s work and husband’s background characteristics • Infant and childhood mortality • Women’s decision making • Awareness about AIDS and other sexually transmitted infections • Other health issues (e.g., knowledge of tuberculosis and hepatitis, injection safety) • Domestic violence

Similarly, the Man’s Questionnaire, used to collect information from ever-married men age 15-49, covered the following topics: • Background characteristics • Knowledge and use of family planning methods • Fertility preferences • Employment and gender roles • Awareness about AIDS and other sexually transmitted infections • Other health issues

The Community Questionnaire, a brief form completed for each rural sample point, included questions about the availability of various types of health facilities and other services, particularly transportation, education, and communication facilities.

All elements of the PDHS data collection activities were pretested in June 2012. Three teams were formed for the pretest, each consisting of a supervisor, a male interviewer, and three female interviewers. One team worked in the Sukkur and Khairpur districts in the province of Sindh, another in the Peshawar and Charsadda districts in Khyber Pakhtunkhwa, and the third in the district of Rawalpindi in Punjab. Each team covered one rural and one urban non-sample area.

Cleaning operations

The processing of the 2012-13 PDHS data began simultaneously with the fieldwork. Completed questionnaires were edited and data entry was carried out immediately in the field by the field editors. The data were uploaded on the same day to enable retrieval in the central office at NIPS in Islamabad, and the Internet File Streaming System was used to transfer data from the field to the central office. The completed questionnaires were then returned periodically from the field to the NIPS office in Islamabad through a courier service, where the data were again edited and entered by data processing personnel specially trained for this task. Thus, all data were entered twice for 100 percent verification. Data were entered using the CSPro computer package. The concurrent processing of the data offered a distinct advantage because of the assurance that the data were error-free and authentic. Moreover, the double entry of data enabled easy identification of errors and inconsistencies, which were resolved via comparisons with the paper questionnaire entries. The secondary editing of the data was completed in the first week of May 2013.

As noted, the PDHS used the CAFE system in the field for the first time. This application was developed and fully tested before teams were deployed in the field. Field editors were selected after careful screening from among the participants who attended the main training exercise. Seven-day training was arranged for field editors so that each editor could enter a sample cluster’s data under the supervision of NIPS senior staff, which enabled a better understanding of the CAFE system. The system was deemed efficient in capturing data immediately in the field and providing immediate feedback to the field teams. Early transfer of data back to the central office enabled the generation of field check tables on a regular basis, an efficient tool for monitoring the fieldwork.

Response rate

A total of 13,944 households were selected for the sample, of which

The First World War (1914–1918) was one of the most significant events of the 20th Century and had a deep and lingering impact on New Zealand society. Just under ten percent of our then population of 1.1 million served overseas, of which more than 18,000 died. There were also over 40,000 hospitalisations due to injury or illness. Nearly every New Zealand family was affected by the impact of the war.

Use this Story Map to find out some details about how and where New Zealander's contributed to the Allied war effort in World War One.

Lest we forget.

During the eighteenth century, it is estimated that France's population grew by roughly fifty percent, from 19.7 million in 1700, to 29 million by 1800. In France itself, the 1700s are remembered for the end of King Louis XIV's reign in 1715, the Age of Enlightenment, and the French Revolution. During this century, the scientific and ideological advances made in France and across Europe challenged the leadership structures of the time, and questioned the relationship between monarchial, religious and political institutions and their subjects. France was arguably the most powerful nation in the world in these early years, with the second largest population in Europe (after Russia); however, this century was defined by a number of costly, large-scale conflicts across Europe and in the new North American theater, which saw the loss of most overseas territories (particularly in North America) and almost bankrupted the French crown. A combination of regressive taxation, food shortages and enlightenment ideologies ultimately culminated in the French Revolution in 1789, which brought an end to the Ancien Régime, and set in motion a period of self-actualization.

War and peace

After a volatile and tumultuous decade, in which tens of thousands were executed by the state (most infamously: guillotined), relative stability was restored within France as Napoleon Bonaparte seized power in 1799, and the policies of the revolution became enforced. Beyond France's borders, the country was involved in a series of large scale wars for two almost decades, and the First French Empire eventually covered half of Europe by 1812. In 1815, Napoleon was defeated outright, the empire was dissolved, and the monarchy was restored to France; nonetheless, a large number of revolutionary and Napoleonic reforms remained in effect afterwards, and the ideas had a long-term impact across the globe. France experienced a century of comparative peace in the aftermath of the Napoleonic Wars; there were some notable uprisings and conflicts, and the monarchy was abolished yet again, but nothing on the scale of what had preceded or what was to follow. A new overseas colonial empire was also established in the late 1800s, particularly across Africa and Southeast Asia. Through most of the eighteenth and nineteenth century, France had the second largest population in Europe (after Russia), however political instability and the economic prioritization of Paris meant that the entire country did not urbanize or industrialize at the same rate as the other European powers. Because of this, Germany and Britain entered the twentieth century with larger populations, and other regions, such as Austria or Belgium, had overtaken France in terms of industrialization; the German annexation of Alsace-Lorraine in the Franco-Prussian War was also a major contributor to this.

World Wars and contemporary France

Coming into the 1900s, France had a population of approximately forty million people (officially 38 million* due to to territorial changes), and there was relatively little growth in the first half of the century. France was comparatively unprepared for a large scale war, however it became one of the most active theaters of the First World War when Germany invaded via Belgium in 1914, with the ability to mobilize over eight million men. By the war's end in 1918, France had lost almost 1.4 million in the conflict, and approximately 300,000 in the Spanish Flu pandemic that followed. Germany invaded France again during the Second World War, and occupied the country from 1940, until the Allied counter-invasion liberated the country during the summer of 1944. France lost around 600,000 people in the course of the war, over half of which were civilians. Following the war's end, the country experienced a baby boom, and the population grew by approximately twenty million people in the next fifty years (compared to just one million in the previous fifty years). Since the 1950s, France's economy quickly grew to be one of the strongest in the world, despite losing the vast majority of its overseas colonial empire by the 1970s. A wave of migration, especially from these former colonies, has greatly contributed to the growth and diversity of France's population today, which stands at over 65 million people in 2020.

BackgroundMany studies concentrate on variation in the hemagglutinin glycoprotein (HA) because of its significance in host immune response, the evolution of this virus is even more complex when other genome segments are considered. Recently, it was found that cytotoxic T lymphocytes (CTL) play an important role in immunity against influenza and most CTL epitopes of human influenza viruses were remarkably conserved. The NP gene has evolved independently in human and avian hosts after 1918 flu pandemic and it has been assigned a putative role as a determinant of host range. Methods and FindingsPhylodynamic patterns of the genes encoding nucleoprotein (NP) of influenza A viruses isolated from 1979–2009 were analyzed by applying the Bayesian Markov Chain Monte Carlo framework to better understand the evolutionary mechanisms of these Taiwanese isolates. Phylogenetic analysis of the NP gene showed that all available H3 worldwide isolates collected so far were genetically similar and divided into two major clades after the year 2004. We compared the deduced amino acid sequences of the NP sequences from human, avian and swine hosts to investigate the emergence of potential adaptive mutations. Overall, selective pressure on the NP gene of human influenza A viruses appeared to be dominated by purifying selection with a mean dN/dS ratio of 0.105. Site-selection analysis of 488 codons, however, also revealed 3 positively selected sites in addition to 139 negatively selected ones. ConclusionsThe demographic history inferred by Bayesian skyline plot showed that the effective number of infections underwent a period of smooth and steady growth from 1998 to 2001, followed by a more recent rise in the rate of spread. Further understanding the correlates of interspecies transmission of influenza A virus genes from other host reservoirs to the human population may help to elucidate the mechanisms of variability among influenza A virus.

In 1800, the population of Latvia was approximately 591,000, a number which would grow steadily throughout the 19th century as reforms in agrarian law and steady improvements in standards of living and production allowed for a significant expansion in population. However, the population of Latvia would peak at just under 2.5 million in 1909, before falling sharply in the First World War. As the battlefield between the German and Russian Empires, Latvia and the other Baltic states were the site of widespread combat, attacks on civilians, and scorched earth campaigns, devastating the country. Even many of those who did not lose their lives in the war were forced to evacuate under orders from the Russian Empire, leading hundreds of thousands to flea eastward. As a result, by the end of the First World War, the population of Latvia would fall to approximately 1.8 million, and would not recover to pre-war population levels until the 1980s.

Following the end of the First World War, Latvia's population would remain largely stagnant at this level, rising slightly before falling back down in the Second World War. However, population growth would increase rapidly in the post-war years, as rapid industrialization by the Soviet Union and sharp decreases in mortality as mass immunization and vaccination would allow for the population to return to pre-World War levels by the 1980s. Latvia's population would begin to decline rapidly with the dissolution of the Soviet Union, however, as significant unemployment and economic turmoil would lead large numbers of Latvians to migrate west to the European Union in search of work, particularly so following Latvia's inclusion into the Schengen Area in 2003. As a result, in 2020, Latvia is estimated to have a population of just under 1.9 million.

This graph shows the total population of Estonia, Latvia and Lithuania in the years between 1922 and 1935, as well as the total number of males and females. After the First World War the Baltic states began claiming their independence from tsarist Russia, as the events of the Russian Revolution took place. Inter-war Estonia The Estonian War of Independence from 1918 to 1920 led to the country's first period of independence, until it became occupied by the Soviet Union again in 1940 during the Second World War. After Estonia gained independence the country experienced a period of political turmoil, including a failed coup d'etat in 1924, and was hit hard by the Great Depression in 1929 before things became more stable in the mid 1930s. Between 1939 and 1945 Estonia's population was devastated by the Second World War, with some estimates claiming that as many as 7.3 percent of all civilians perished as a result of the conflict. From the graph we can see the population grew by 119 thousand people during the 12 years shown, growing from 1.107 million to 1.126 million. The number of women was also higher than the number of men during this time, by 67 thousand in 1922 and 68 thousand in 1934. Inter-war Latvia For Latvia, Independence was a hard-won struggle that had devastated the population in the late 1910s. Similarly to Estonia, the advent of independence brought many challenges to Latvia, and a period of political and economic turmoil followed, which was exacerbated by the Great Depression in 1929. After economic recovery began in 1933, and a coup d'etat established stricter control in 1934, the Latvian economy and political landscape became more stable and the quality of life improved. This lasted until the Second World War, where Latvia became one of the staging grounds of Germany's war against Soviet Russia, and approximately 12.5 percent of all civilians died. From the data we can see that Latvia's population between 1925 and 1935 grew steadily by 95,000 in this decade, with the number of men and women growing at a similar rate. Inter-war Lithuania Lithuania's experience in the interwar period was slightly different to that of Latvia and Estonia. The end of the First World War led to a growing movement for independence from German, Russian or Polish influence, however these countries were reluctant to cede control to one another, and independence was finally achieved in 1922. A right wing dictatorship was established in 1926, which maintained political and civil control until the outbreak of the Second World War, however interference from other nations, particularly Germany, was ever-present in Lithuanian economic activity. From the graph we have only one set of figures, showing that the Lithuanian population was just over 2 million in 1929, with approximately 5 percent more women than men. World War II again devastated Lithuania's population, with almost 14.4 percent of the entire population falling during the conflict.

This statistic shows the total population of men and women in Poland from 1900 until 2020. When this graph begins in 1900, Poland was not a united and independent country, and was split between the Austro-Hungarian, German and Russian empires. Poland eventually became a state in 1918, after the events of the First World War, however it's borders were further to the east than they are today. This statistic shows the populations of Poland within todays borders, and from it we can see that the population of men and women were relatively similar at 12.5 and 12.6 million respectively. In the inter-war years the difference in the number of men and women grew as a result of the First World War and the subsequent conflict to the east, where there were approximately 0.9 million more women.

The next entries in the graph come in 1946, where Poland's population falls to 23.9 million. The number of men falls by almost 5 million and the number of women falls by over 3.5 million. Poland was one of the most devastated countries during the Second World War, due to it's location it was the staging ground for much of the violence during Germany's war against Russia, and the civilian population was devastated during both occupations. With up to 5.8 million total deaths, approximately 17 percent of the total Polish population died during the Second World War, which is a higher proportion than any other country involved in the war.

After the war, Poland's population grew from 1946 onwards until the turn of the century, the difference in the number of men and women remained at around one million people, and the total population exceeded its pre-war levels in the late 1960s. Like many other Eastern European countries, with the fall of the iron curtain in the early 1990s, the population had greater freedom of movement and growth began to slow. By 2000 the population growth was declining, the number of men was and women were at 18.7 and 19.4 million respectively, and both populations then fell by 2015, with the number of men declining at a slightly faster rate than the number of women.

In 1844, Romania had a population of just 3.6 million people. During the early entries in this data, Romania's borders were very different and much smaller than today, and control of this area often switched hands between the Austrian, Ottoman and Russian empires. The populations during this time are based on estimates made for incomplete census data, and they show that the population grows from 3.6 million in 1844, doubling to 7.2 million in 1912, part of this growth is due to a high natural birth rate during this period, but also partly due to the changing of Romania's borders and annexation of new lands. During this time Romania gained its independence from the Ottoman Empire as a result of the Russo-Turkish War in 1878, and experienced a period of increased stability and progress.

Between 1912 and 1930 the population of Romania grew by over 10 million people. The main reason for this is the huge territories gained by Romania in the aftermath of the First World War. During the war Romania remained neutral for the first two years, after which it joined the allies; however, it was very quickly defeated and overrun by the Central Powers, and in total it lost over 600 thousand people as a direct result of the war. With the collapse of the Austro-Hungarian and Russian empires after the war, Romania gained almost double it's territory, which caused the population to soar to 18.1 million in 1930. The population then decreases by 1941 and again by 1948, as Romania seceded territory to neighboring countries and lost approximately half a million people during the Second World War. From 1948 onwards the population begins to grow again, reaching it's peak at 23.5 million people in 1990.

Like many other Eastern European countries, there was very limited freedom of movement from Romania during the Cold War, and communist rule was difficult for the Romanian people. The Romanian Revolution in 1989 ended communist rule in the country, Romania transitioned to a free-market society and movement from the country was allowed. Since then the population has fallen each year as more and more Romanians move abroad in search of work and opportunities. The population is expected to fall to 19.2 million in 2020, which is over 4 million fewer people than it had in 1990.

At the beginning of the 19th century, the area of modern-day Italy, at the time a collection of various states and kingdoms, was estimated to have a population of nineteen million, a figure which would grow steadily throughout the century, and by the establishment of the Kingdom of Italy in 1861, the population would rise to just over 26 million.

Italy’s population would see its first major disruption during the First World War, as Italy would join the Allied Forces in their fight against Austria-Hungary and Germany. In the First World War, Italy’s population would largely stagnate at 36 million, only climbing again following the end of the war in 1920. While Italy would also play a prominent role in the Second World War, as the National Fascist Party-led country would fight alongside Germany against the Allies, Italian fatalities from the war would not represent a significant percentage of Italy’s population compared to other European countries in the conflict. As a result, Italy would exit the Second World War with a population of just over 45 million.

From this point onwards the Italian economy started to recover from the war, and eventually boomed, leading to increased employment and standards of living, which facilitated steady population growth until the mid-1980s, when falling fertility and birth rates would cause growth to largely cease. From this point onward, the Italian population would remain at just over 57 million, until the 2000s when it began growing again due to an influx of migrants, peaking in 2017 at just over 60 million people. In the late 2010s, however, the Italian population began declining again, as immigration slowed and the economy weakened. As a result, in 2020, Italy is estimated to have fallen to a population of 59 million.

Over the course of the long nineteenth century, Estonia's population almost tripled, from 0.33 million in 1800, to over one million at the outbreak of the First World War. Throughout this time, Estonia was a part of the Russian Empire, however Germany then annexed the region during the First World War; when the German army eventually retreated in 1918, Estonian forces prevented Russia from re-taking the area in the Estonian War of Independence, and an independent Estonian Republic was gradually established between 1918 and 1920. Relative to its size and population, Estonia developed into a prosperous and peaceful nation in the interwar period, and Estonian language and culture thrived, although political stability proved difficult for the Baltic state.

Estonia in WWII Estonia's independence was short lived, as the country was then annexed by the Soviet Union as part of the secret Molotov-Ribbentrop Pact between Germany and the Soviets. The invasion was achieved with little-to-no conflict, as Estonia capitulated when faced with the vastly superior military and navy of the Soviet Union. Annexation became official in June 1940; a puppet, communist government was quickly established, and many military and political rivals were imprisoned or executed under Soviet control. When Germany invaded the Soviet Union the following year, they quickly took control of Estonia, but simply replaced the Soviet Union's rule with their own, and did not grant re-establish sovereignty as many Estonians had expected or hoped for. By the war's end, Estonia suffered approximately 83,000 deaths at the hands of the Soviet Union and Germany, with almost 50,000 of these civilian deaths, and the rest were fatalities of Estonian soldiers who were forced to fight in other nations' armies.

Post-war Estonia Following the war, Estonia remained under Soviet control, and between 1950 and 1990, the population of Estonia grew steadily, from 1.1 million to almost 1.6 million. In the wake of the Soviet Union's collapse, Estonia established a rapid, but peaceful independence in 1991; and the population dropped by roughly ten percent by the end of the century. This was mostly due to non-Estonians returning to their country or region of origin, although a wave of Estonian emigration soon followed. Estonia joined the European Union in 2004, and from 2000 until 2015, Estonia's population continued to fall, reaching just 1.3 million people in 2015. Recent years, however, have seen a reversal in this trend, with limited growth since 2015; although demographers predict that Estonia's population will drop below one million people in the next half-century. The past three decades have marked the longest continuous period in the past 800 years, where the region of Estonia was not under German, Polish, Russian or Scandinavian control.

Throughout the 19th century, what we know today as Poland was not a united, independent country; apart from a brief period during the Napoleonic Wars, Polish land was split between the Austro-Hungarian, Prussian (later German) and Russian empires. During the 1800s, the population of Poland grew steadily, from approximately nine million people in 1800 to almost 25 million in 1900; throughout this time, the Polish people and their culture were oppressed by their respective rulers, and cultural suppression intensified following a number of uprisings in the various territories. Following the outbreak of the First World War, it is estimated that almost 3.4 million men from Poland served in the Austro-Hungarian, German and Russian armies, with a further 300,000 drafted for forced labor by the German authorities. Several hundred thousand were forcibly resettled in the region during the course of the war, as Poland was one of the most active areas of the conflict. For these reasons, among others, it is difficult to assess the extent of Poland's military and civilian fatalities during the war, with most reliable estimates somewhere between 640,000 and 1.1 million deaths. In the context of present-day Poland, it is estimated that the population fell by two million people in the 1910s, although some of this was also due to the Spanish Flu pandemic that followed in the wake of the war.

Poland 1918-1945

After more than a century of foreign rule, an independent Polish state was established by the Allied Powers in 1918, although it's borders were considerably different to today's, and were extended by a number of additional conflicts. The most significant of these border conflicts was the Polish-Soviet War in 1919-1920, which saw well over 100,000 deaths, and victory helped Poland to emerge as the Soviet Union's largest political and military rival in Eastern Europe during the inter-war period. Economically, Poland struggled to compete with Europe's other powers during this time, due to its lack of industrialization and infrastructure, and the global Great Depression of the 1930s exacerbated this further. Political corruption and instability was also rife in these two decades, and Poland's leadership failed to prepare the nation for the Second World War. Poland had prioritized its eastern defenses, and some had assumed that Germany's Nazi regime would see Poland as an ally due to their shared rivalry with the Soviet Union, but this was not the case. Germany invaded Poland on September 1, 1939, in the first act of the War, and the Soviet Union launched a counter invasion on September 17; Germany and the Soviet Union had secretly agreed to do this with the Molotov-Ribbentrop Pact in August, and had succeeded in taking the country by September's end. When Germany launched its invasion of the Soviet Union in 1941 it took complete control of Poland, which continued to be the staging ground for much of the fighting between these nations. It has proven difficult to calculate the total number of Polish fatalities during the war, for a variety of reasons, however most historians have come to believe that the figure is around six million fatalities, which equated to almost one fifth of the entire pre-war population; the total population dropped by four million throughout the 1940s. The majority of these deaths took place during the Holocaust, which saw the Nazi regime commit an ethnic genocide of up to three million Polish Jews, and as many as 2.8 million non-Jewish Poles; these figures do not include the large number of victims from other countries who died after being forcefully relocated to concentration camps in Poland.

Post-war Poland

The immediate aftermath of the war was also extremely unorganized and chaotic, as millions were forcefully relocated from or to the region, in an attempt to create an ethnically homogenized state, and thousands were executed during this process. A communist government was quickly established by the Soviet Union, and socialist social and economic policies were gradually implemented over the next decade, as well as the rebuilding, modernization and education of the country. In the next few decades, particularly in the 1980s, the Catholic Church, student groups and trade unions (as part of the Solidarity movement) gradually began to challenge the government, weakening the communist party's control over the nation (although it did impose martial law and imprison political opponent throughout the early-1980s). Increasing civil unrest and the weakening of Soviet influence saw communism in Poland come to an end in the elections of 1989. Throughout the 1990s, Poland's population growth stagnated at around 38.5 million people, before gradually decreasing since the turn of the millennium, to 37.8 million people in 2020. This decline was mostly due to a negative migration rate, as Polish workers could now travel more freely to Western European countries in search of work, facilitated by Pola...

Bulgaria, with the help of the Russian Empire, achieved independence from the Ottoman Empire in 1878. In the decades before independence, Bulgaria's population had remained between 2.2 and 2.8 million people, and growth was much slower then the following century. Although most at the time assumed that it would become a Russian ally, Bulgaria defied the expectations and aligned itself with the western powers, and developed into a modern European state by the turn in the late 1800s. Bulgaria at war In the early twentieth century Bulgaria was involved in both World Wars, as well as two Balkan Wars. The Balkan states were unhappy with the borders assigned to them by the western powers, and instead wanted to re-draw them based on the dispersal of ethnic groups. This led to the first Balkan War in 1912, which saw Bulgaria fight alongside Greece and Serbia against the Ottomans. Bulgaria fought the second Balkan War on all sides, this time against Greece, Serbia, Romania and the Ottomans, as the dispute over borders continued. Bulgaria was defeated this time, and sustained heavy casualties, amassing in 58 thousand fatalities and over 100 thousand wounded in the two wars.

In the First World War, Bulgaria remained neutral at first, in order to recover from the previous wars, but then aligned itself with the Central powers in 1915, and played a vital role in maintaining their control in the Balkans. While Bulgaria was initially successful, its allies weakened as the war progressed, and then Bulgaria eventually succumbed to Allied forces and surrendered in 1918, with almost 200 thousand Bulgarians dying as a result of the war. The interwar years was a period of political and economic turmoil, and when control was re-established, Bulgaria was then able to maintain it's neutrality throughout most of the Second World War, (although there was some conflict and bombings in certain areas). Rise and fall of communism After the war, Bulgaria became a communist state, and life became harsh for the civil population there until the late 1950s when the standard of living rose again. In the late 1980s, like many Eastern European countries, Bulgaria experienced economic decline as the communist system began to collapse. Political failures also contributed to this, and approximately 300 thousand Bulgarian Turks migrated to Turkey, greatly weakening the agricultural economy. This trend of mass migration abroad continued after the fall of the iron curtain, as well as the rise of unemployment. Bulgaria reached it's peak population size in 1985 at 8.98 million inhabitants, but then the number decreases each year, and is expected to be 6.94 million in 2020. This drop in population size has been attributed to the economic collapse at the end of communism in Eastern Europe, causing many to leave the country in search of work elsewhere. Bulgaria also has one of the lowest fertility rates in the world, with 8.7 births per 1,000 people per year (in 2018).