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.

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.

There were 694,685 live births recorded in the United Kingdom in 2021, compared with 681,560 in the previous year. Between 1887 and 2021 the year with the highest number of live births was 1920 when there were approximately 1.13 million births, while the year with the fewest births was 1977, when there were just 657,038 births. Birth rate at a historic low in 2020 At 10.2 births per 1,000 people, the birth rate of the United Kingdom in 2020 was at a historic low. After witnessing a twenty-first century high of 12.9 in 2010, the birth rate gradually declined before a sharp decrease was recorded between 2012 and 2013. Although there was a slight uptick in the birth rate in 2021, when there were 10.4 births per 1,000 people, the total fertility rate reached a low of 1.53 births per woman in the same year. As well as falling birth and fertility rates, the average age of mothers has been increasing. In 1991, the average age of mothers at childbirth was 27.7 years, compared with 30.9 years in 2021. UK population reaches 67 million In 2022, the overall population of the United Kingdom was almost 67.6 million people. Of the four countries that comprise the UK, England has by far the highest population, at 57.1 million, compared with 5.45 million in Scotland, 3.13 million in Wales, and 1.91 million in Northern Ireland. These countries are far less densely populated than England, especially when compared to London, which had approximately 5,630 people per square kilometer, compared with just 70 in Scotland. After London, North West England was the second-most densely populated area of the UK, which includes the large metropolitan areas of the cities of Manchester, and Liverpool

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 t...

In 1800, the population of the region of present-day India was approximately 169 million. The population would grow gradually throughout the 19th century, rising to over 240 million by 1900. Population growth would begin to increase in the 1920s, as a result of falling mortality rates, due to improvements in health, sanitation and infrastructure. However, the population of India would see it’s largest rate of growth in the years following the country’s independence from the British Empire in 1948, where the population would rise from 358 million to over one billion by the turn of the century, making India the second country to pass the billion person milestone. While the rate of growth has slowed somewhat as India begins a demographics shift, the country’s population has continued to grow dramatically throughout the 21st century, and in 2020, India is estimated to have a population of just under 1.4 billion, well over a billion more people than one century previously. Today, approximately 18% of the Earth’s population lives in India, and it is estimated that India will overtake China to become the most populous country in the world within the next five years.

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.

The island of Ireland is split into 32 different counties, and from 1800 until 1921 the whole island was a part of the United Kingdome of Great Britain and Ireland (although Britain had been a controlling presence on the island for considerably longer than this). In 1921 the island was split into two separate states, where the six counties with the highest population of Protestants formed part of the United Kingdom of Great Britain and Northern Ireland, and the other 26 counties became the Independent Republic of Ireland. From 1821 until 1841, the population of these 26 counties was growing steadily, until the Great Famine from 1845 to 1849 swept across the island, particularly devastating the west and south.

The famine was caused by a Europe-wide potato blight that contributed to mass starvation and death throughout the continent, although it's impact on Ireland was much harsher than anywhere else. The potato blight affected Ireland so severely as the majority of potatoes in Ireland were of a single variety which allowed the disease to spread much faster than in other countries. People in the west and south of Ireland were particularly dependent on potatoes, and these areas were affected more heavily than the north and west, where flax and cereals were the staple. As the potato blight spread, the population became increasingly reliant on dairy and grain products, however a lot of these resources were relocated by the British military to combat food shortages in Britain. Due to disproportional dependency on potatoes, and mismanagement by the British government, over one million people died and a further one million emigrated. The Great Famine lasted from just 1845 to 1849, but it's legacy caused almost a century of population decline, and to this day, the population of Ireland has never exceeded it's pre-famine levels.

The population decline continued well into the twentieth century, during which time the Republic of Ireland achieved independence from the British Empire. After centuries of fighting and rebellion against British rule, Irish nationalists finally gained some independence from Britain in 1921, establishing an Irish Republic in the 26 counties. There was a lot of conflict in Ireland in the early 1900s, through the War of Independence and Irish Civil War, however the population of the Republic began growing again from the 1960s onwards as the quality of life improved and the emigration rate declined. The population was at it's lowest from 1926 to 1971, where it remained at just under three million, but in the following fifty years the population has grown by over two million people.

The history of modern Brazil begins in the year 1500 when Pedro Álvares Cabral arrived with a small fleet and claimed the land for the Portuguese Empire. With the Treaty of Torsedillas in 1494, Spain and Portugal agreed to split the New World peacefully, thus allowing Portugal to take control of the area with little competition from other European powers. As the Portuguese did not arrive with large numbers, and the indigenous population was overwhelmed with disease, large numbers of African slaves were transported across the Atlantic and forced to harvest or mine Brazil's wealth of natural resources. These slaves were forced to work in sugar, coffee and rubber plantations and gold and diamond mines, which helped fund Portuguese expansion across the globe. In modern history, transatlantic slavery brought more Africans to Brazil than any other country in the world. This combination of European, African and indigenous peoples set the foundation for what has become one of the most ethnically diverse countries across the globe.

Independence and Monarchy By the early eighteenth century, Portugal had established control over most of modern-day Brazil, and the population more than doubled in each half of the 1800s. The capital of the Portuguese empire was moved to Rio de Janeiro in 1808 (as Napoleon's forces moved closer towards Lisbon), making this the only time in European history where a capital was moved to another continent. The United Kingdom of Portugal, Brazil and the Algarves was established in 1815, and when the Portuguese monarchy and capital returned to Lisbon in 1821, the King's son, Dom Pedro, remained in Brazil as regent. The following year, Dom Pedro declared Brazil's independence, and within three years, most other major powers (including Portugal) recognized the Empire of Brazil as an independent monarchy and formed economic relations with it; this was a much more peaceful transition to independence than many of the ex-Spanish colonies in the Americas. Under the reign of Dom Pedro II, Brazil's political stability remained relatively intact, and the economy grew through its exportation of raw materials and economic alliances with Portugal and Britain. Despite pressure from political opponents, Pedro II abolished slavery in 1850 (as part of a trade agreement with Britain), and Brazil remained a powerful, stable and progressive nation under Pedro II's leadership, in stark contrast to its South American neighbors. The booming economy also attracted millions of migrants from Europe and Asia around the turn of the twentieth century, which has had a profound impact on Brazil's demography and culture to this day.

The New Republic

Despite his popularity, King Pedro II was overthrown in a military coup in 1889, ending his 58 year reign and initiating six decades of political instability and economic difficulties. A series of military coups, failed attempts to restore stability, and the decline of Brazil's overseas influence contributed greatly to a weakened economy in the early 1900s. The 1930s saw the emergence of Getúlio Vargas, who ruled as a fascist dictator for two decades. Despite a growing economy and Brazil's alliance with the Allied Powers in the Second World War, the end of fascism in Europe weakened Vargas' position in Brazil, and he was eventually overthrown by the military, who then re-introduced democracy to Brazil in 1945. Vargas was then elected to power in 1951, and remained popular among the general public, however political opposition to his beliefs and methods led to his suicide in 1954. Further political instability ensued and a brutal, yet prosperous, military dictatorship took control in the 1960s and 1970s, but Brazil gradually returned to a democratic nation in the 1980s. Brazil's economic and political stability fluctuated over the subsequent four decades, and a corruption scandal in the 2010s saw the impeachment of President Dilma Rousseff. Despite all of this economic instability and political turmoil, Brazil is one of the world's largest economies and is sometimes seen as a potential superpower. The World Bank classifies it as a upper-middle income country and it has the largest share of global wealth in Latin America. It is the largest Lusophone (Portuguese-speaking), and sixth most populous country in the world, with a population of more than 210 million people.

In 1800, the region of present-day Iraq had an estimated population of just over one million people. The population of Iraq would grow slowly throughout the 19th century, reaching just over two million by the beginning of the 20th century. However, Iraq’s population would begin to rise rapidly in the 1920s, as modernization programs implemented by the British administration, aided by the discovery of oil in 1927, would see mortality rates fall and living standards rise for much of the country. As a result, Iraq would grow to have a population of just under seven million by the time of the Iraqi Republic's establishment in 1958. Population growth would continue to increase following the creation of the republic, doubling to fourteen million by the 1980s; according to these estimates, the Iran-Iraq War of the 1980s did little to change the trajectory of Iraq's population growth, nor did the Gulf War of 1990-1991, despite Iraq suffering up to half a million fatalities in these conflicts. Iraq's population growth did slow in the early 2000s however, with the U.S.-led invasion of Iraq in 2003. While the initial invasion would see relatively few casualties (compared to previous conflicts), the resulting economic turmoil and political instability, combined with the rise of the Iraqi insurgency and civil war in the region, would cause population growth to slow for several years. Population growth would recover starting in the 2010s, and by 2020, Iraq is estimated to have a population of just over forty million.

The 2021 Northern Ireland Census marked the first time since records began where the Catholic share of the population was larger than the combined Protestant share. In 2021, over 42 percent of the population classified themselves as Catholic or from a Catholic background, in comparison with 37 percent classified as Protestant or from a Protestant background. Additionally, the share of the population with no religion (or those who did not answer) was 19 percent; larger than any individual Protestant denomination. This marks a significant shift in demographic and societal trends over the past century, as Protestants outnumbered Catholics by roughly 2:1 when Northern Ireland was established in the 1920s. Given the Catholic community's historic tendency to be in favor of a united Ireland, many look to the changing religious composition of the population when assessing the potential for Irish reunification. Religion's historical influence A major development in the history of British rule in ireland was the Plantation of Ulster in the 1600s, where much of the land in the north (historically the most rebellious region) was seized from Irish Catholics and given to Protestant settlers from Britain (predominantly Scots). This helped establish Protestant dominance in the north, created a large section of the population loyal to the British crown, and saw a distinct Ulster-Scots identity develop over time. In the 1920s, the republican movement won independence for 26 of Ireland's 32 counties, however, the six counties in Ulster with the largest Protestant populations remained part of the UK, as Northern Ireland. Following partition, structural inequalities between Northern Ireland's Protestant and Catholic communities meant that the Protestant population was generally wealthier, better educated, more politically empowered, and had better access to housing, among other advantages. In the 1960s, a civil rights movement then emerged for equal rights and status for both sides of the population, but this quickly turned violent and escalated into a the three-decade long conflict now known as the Troubles.

The Troubles was largely fought between nationalist/republican paramilitaries (mostly Catholic), unionist/loyalist paramilitaries (mostly Protestant), and British security forces (including the police). This is often described as a religious conflict, however it is more accurately described as an ethnic and political conflict, where the Catholic community generally favored Northern Ireland's reunification with the rest of the island, while the Protestant community wished to remain in the UK. Paramilitaries had a large amount of support from their respective communities in the early years of the Troubles, but this waned as the conflict progressed into the 1980s and 1990s. Demographic and societal trends influenced the religious composition of Northern Ireland's population in these decades, as the Catholic community had higher fertility rates than Protestant communities, while the growing secularism has coincided with a decline in those identifying as Protestant - the dip in those identifying as Catholic in the 1970s and 1980s was due to a protest and boycott of the Census. The Troubles came to an end in 1998, and divisions between both sides of the community have drastically fallen, although they have not disappeared completely.

Humans have been living on the continent of Australia (name derived from "Terra Australis"; Latin for "the southern land") for approximately 65,000 years, however population growth was relatively slow until the nineteenth century. Europeans had made some contact with Australia as early as 1606, however there was no significant attempt at settlement until the late eighteenth century. By 1800, the population of Australia was approximately 350,000 people, and the majority of these were Indigenous Australians. As colonization progressed the number of ethnic Europeans increased while the Australian Aboriginal population was decimated through conflict, smallpox and other diseases, with some communities being exterminated completely, such as Aboriginal Tasmanians. Mass migration from Britain and China After the loss of its American colonies in the 1780s, the British Empire looked to other parts of the globe to expand its sphere of influence. In Australia, the first colonies were established in Sydney, Tasmania and Western Australia. Many of these were penal colonies which became home to approximately 164,000 British and Irish convicts who were transported to Australia between 1788 and 1868. As the decades progressed, expansion into the interior intensified, and the entire country was claimed by Britain in 1826. Inland colonization led to further conflict between European settlers and indigenous Australians, which cost the lives of thousands of natives. Inward expansion also saw the discovery of many natural resources, and most notably led to the gold rushes of the 1850s, which attracted substantial numbers of Chinese migrants to Australia. This mass migration from non-European countries eventually led to some restrictive policies being introduced, culminating with the White Australia Policy of 1901, which cemented ethnic-European dominance in Australian politics and society. These policies were not retracted until the second half of the 1900s. Independent Australia Australia changed its status to a British dominion in 1901, and eventually became independent in 1931. Despite this, Australia has remained a part of the British Commonwealth, and Australian forces (ANZAC) fought with the British and their Allies in both World Wars, and were instrumental in campaigns such as Gallipoli in WWI, and the South West Pacific Theater in WWII. The aftermath of both wars had a significant impact on the Australian population, with approximately 90 thousand deaths in both world wars combined, as well as 15 thousand deaths as a result of the Spanish flu pandemic following WWI, although Australia experienced a significant baby boom following the Second World War. In the past fifty years, Australia has promoted immigration from all over the world, and now has one of the strongest economies and highest living standards in the world, with a population that has grown to over 25 million people in 2020.

In 1800, the population of the area of modern-day Bangladesh was estimated to be just over 19 million, a figure which would rise steadily throughout the 19th century, reaching over 26 million by 1900. At the time, Bangladesh was the eastern part of the Bengal region in the British Raj, and had the most-concentrated Muslim population in the subcontinent's east. At the turn of the 20th century, the British colonial administration believed that east Bengal was economically lagging behind the west, and Bengal was partitioned in 1905 as a means of improving the region's development. East Bengal then became the only Muslim-majority state in the eastern Raj, which led to socioeconomic tensions between the Hindu upper classes and the general population. Bengal Famine During the Second World War, over 2.5 million men from across the British Raj enlisted in the British Army and their involvement was fundamental to the war effort. The war, however, had devastating consequences for the Bengal region, as the famine of 1943-1944 resulted in the deaths of up to three million people (with over two thirds thought to have been in the east) due to starvation and malnutrition-related disease. As the population boomed in the 1930s, East Bengal's mismanaged and underdeveloped agricultural sector could not sustain this growth; by 1942, food shortages spread across the region, millions began migrating in search of food and work, and colonial mismanagement exacerbated this further. On the brink of famine in early-1943, authorities in India called for aid and permission to redirect their own resources from the war effort to combat the famine, however these were mostly rejected by authorities in London. While the exact extent of each of these factors on causing the famine remains a topic of debate, the general consensus is that the British War Cabinet's refusal to send food or aid was the most decisive. Food shortages did not dissipate until late 1943, however famine deaths persisted for another year. Partition to independence Following the war, the movement for Indian independence reached its final stages as the process of British decolonization began. Unrest between the Raj's Muslim and Hindu populations led to the creation of two separate states in1947; the Muslim-majority regions became East Pakistan (now Bangladesh) and West Pakistan (now Pakistan), separated by the Hindu-majority India. Although East Pakistan's population was larger, power lay with the military in the west, and authorities grew increasingly suppressive and neglectful of the eastern province in the following years. This reached a tipping point when authorities failed to respond adequately to the Bhola cyclone in 1970, which claimed over half a million lives in the Bengal region, and again when they failed to respect the results of the 1970 election, in which the Bengal party Awami League won the majority of seats. Bangladeshi independence was claimed the following March, leading to a brutal war between East and West Pakistan that claimed between 1.5 and three million deaths in just nine months. The war also saw over half of the country displaced, widespread atrocities, and the systematic rape of hundreds of thousands of women. As the war spilled over into India, their forces joined on the side of Bangladesh, and Pakistan was defeated two weeks later. An additional famine in 1974 claimed the lives of several hundred thousand people, meaning that the early 1970s was one of the most devastating periods in the country's history. Independent Bangladesh In the first decades of independence, Bangladesh's political hierarchy was particularly unstable and two of its presidents were assassinated in military coups. Since transitioning to parliamentary democracy in the 1990s, things have become comparatively stable, although political turmoil, violence, and corruption are persistent challenges. As Bangladesh continues to modernize and industrialize, living standards have increased and individual wealth has risen. Service industries have emerged to facilitate the demands of Bangladesh's developing economy, while manufacturing industries, particularly textiles, remain strong. Declining fertility rates have seen natural population growth fall in recent years, although the influx of Myanmar's Rohingya population due to the displacement crisis has seen upwards of one million refugees arrive in the country since 2017. In 2020, it is estimated that Bangladesh has a population of approximately 165 million people.

In 1820, the islands of present-day New Zealand had a population of approximately 100,000 people. This figure would fall until the early 1840s, partly as a result of European diseases brought by colonizers, and a series of destructive inter-tribal wars among the Māori peoples. These conflicts were named the Musket Wars due to the European weapons whose introduction instigated the conflicts, and the wars saw the deaths of between 20,000 and 40,000 Māori, from 1807 to 1837. After falling to just 82 thousand in the 1840s, the population would begin to rise again in 1841 following the establishment of New Zealand as an official British colony, with a strong promotion of European settlement by British citizens sponsored by the Church of England. European migration to New Zealand was low in these early decades, but increased in the mid-19th century, particularly following the discovery of gold in New Zealand’s South Island in the 1860s. This growth would continue throughout the 1870s, in part the result of a strong promotion of mass migration from Britain by Premier Julius Vogel’s administration.

Early 20th century However, between 1881 and the 1920s, the New Zealand government heavily restricted Asiatic migration to the islands, resulting in a fall of population growth rate, which would remain until the Second World War. The country would experience a dip in population during the First World War, in which New Zealand would suffer approximately 18,000 military fatalities, and another 9,000 lost to the coinciding Spanish Flu epidemic. The population would stagnate again in the Second World War, which resulted in the death of almost 12,000 New Zealanders. In the years following the war, New Zealand would see a significant increase in population due to the mixture of a baby boom and a migrant spike from Europe and Asia, following a large demand for unskilled labor. Recent decades This increase continued for several decades, until international factors, such as the oil crises of 1973 and 1979, and the UK's accession to the European Economic Communities (which ended most of New Zealand's trade agreements with Britain; it's largest trade partner), greatly weakened New Zealand's economy in the 1970s. As a result, population growth stagnated during the 1970s, while economic problems persisted into the early 2000s. In contrast, the Great Recession of 2008 did not impact New Zealand as severely as most other developed nations, which allowed the economy to emerge as one of the fastest growing in the world, also leading to dropped unemployment levels and increased living standards. In 2020, with a population of almost five million people, New Zealand is regarded as one of the top countries in the world in terms of human development, quality of life and social freedoms.

In 1800, the population of the area of modern-day Pakistan was estimated to be just over 13 million. Population growth in the 19th century would be gradual in the region, rising to just 19 million at the turn of the century. In the early 1800s, the British Empire slowly consolidated power in the region, eventually controlling the region of Pakistan from the mid-19th century onwards, as part of the British Raj. From the 1930s on, the population's growth rate would increase as improvements in healthcare (particularly vaccination) and sanitation would lead to lower infant mortality rates and higher life expectancy. Independence In 1947, the Muslim-majority country of Pakistan gained independence from Britain, and split from the Hindu-majority country of India. In the next few years, upwards of ten million people migrated between the two nations, during a period that was blemished by widespread atrocities on both sides. Throughout this time, the region of Bangladesh was also a part Pakistan (as it also had a Muslim majority), known as East Pakistan; internal disputes between the two regions were persistent for over two decades, until 1971, when a short but bloody civil war resulted in Bangladesh's independence. Political disputes between Pakistan and India also created tension in the first few decades of independence, even boiling over into some relatively small-scale conflicts, although there was some economic progress and improvements in quality of life for Pakistan's citizens. The late 20th century was also characterized by several attempts to become democratic, but with intermittent periods of military rule. Between independence and the end of the century, Pakistan's population had grown more than four times in total. Pakistan today Since 2008, Pakistan has been a functioning democracy, with an emerging economy and increasing international prominence. Despite the emergence of a successful middle-class, this is prosperity is not reflected in all areas of the population as almost a quarter still live in poverty, and Pakistan ranks in the bottom 20% of countries according to the Human Development Index. In 2020, Pakistan is thought to have a total population of over 220 million people, making it the fifth-most populous country in the world.

In the United Kingdom, the crude birth rate in 1800 was 37 live births per thousand people, meaning that 3.7 percent of the population had been born in that year. From 1800 until 1830, the crude birth rate jumped between 35 and 45, before plateauing between 35 and 37 until the 1880s. From 1880 until the Second World War, the crude birth rate dropped to just under fifteen births per one thousand people, with the only increase coming directly after World War One. After WWII, the United Kingdom experienced a baby boom, as many soldiers returned home and the economy recovered, however this boom stopped in the late 1960s and the crude birth rate went into decline again. From the late 1970s until today, the crude birth rate has remained between eleven and fourteen, and is expected to be 11.5 in 2020.

This statistic shows the proportion of women remaining childless in England and Wales as of 2016, by cohort. For women born in 1920, 21 per cent remained childless by their 46th birthday. This fell to one in ten for women born in 1945. The cohort of women who have most recently come to the end of their official childbearing period were born in 1971. In this cohort, 18 percent remained childless which marked an increase of women with children in comparison to the previous cohort.

It is estimated that the Second World War was responsible for the deaths of approximately 3.76 percent of the world's population between 1939 and 1945. In 2022, where the world's population reached eight billion, this would be equal to the death of around 300 million people.

The region that experienced the largest loss of life relative to its population was the South Seas Mandate - these were former-German territories given to the Empire of Japan through the Treaty of Versailles following WWI, and they make up much of the present-day countries of the Marshall Islands, Micronesia, the Northern Mariana Islands (U.S. territory), and Palau. Due to the location and strategic importance of these islands, they were used by the Japanese as launching pads for their attacks on Pearl Harbor and in the South Pacific, while they were also taken as part of the Allies' island-hopping strategy in their counteroffensive against Japan. This came at a heavy cost for the local populations, a large share of whom were Japanese settlers who had moved there in the 1920s and 1930s. Exact figures for both pre-war populations and wartime losses fluctuate by source, however civilian losses in these islands were extremely high as the Japanese defenses resorted to more extreme measures in the war's final phase.

In the year 1500, the share of Western Europe's population living in urban areas was just six percent, but this rose to 31 percent by the end of the 19th century. Despite this drastic change, development was quite slow between 1500 and 1800, and it was not until the industrial revolution when there was a spike in urbanization. As Britain was the first region to undergo the industrial revolution, from around the 1760s until the 1840s, these areas were the most urbanized in Europe by 1890. The Low Countries Prior to the 19th century, Belgium and the Netherlands had been the most urbanized regions due to the legacy of their proto-industrial areas in the medieval period, and then the growth of their port cities during the Netherlands' empirical expansion (Belgium was a part of the Netherlands until the 1830s). Belgium was also quick to industrialize in the 1800s, and saw faster development than its larger, more economically powerful neighbors, France and Germany. Least-urban areas Ireland was the only Western European region with virtually no urbanization in the 16th and 17th century, but the industrial growth of Belfast and Dublin (then major port cities of the British Empire) saw this change by the late-1800s. The region of Scandinavia was the least-urbanized area in Western Europe by 1890, but it saw rapid economic growth in Europe during the first half of the following century.

Between 1821 and 1921, the entire island of Ireland was a part of the United Kingdom of Great Britain and Ireland, after both islands were united by the Act of Union in 1800. This graph shows only the population of the six counties of Ireland that would go on to become Northern Ireland. The population was just under 1.4 million in 1821 and grew to 1.7 million in the next twenty years.

Between 1845 and 1849 the Great Famine devastated the overall population of Ireland, causing the deaths of approximately one million people, and causing a further million to emigrate. Although the famine affected the population of the west and south of Ireland much more severely than the north, the population of the six counties still fell by over 200,000 people between 1841 and 1851. The population then continued to fall, reaching it's lowest point in the 1890s where it was 1.2 million. The Northern Irish population then grows slowly until the mid to late 1900s, during which time the state of Northern Ireland was founded in 1921. The population the reaches over 1.54 million in the 1960s, before it falls again in the 1970s. This drop in population coincides with the outbreak and the most violent decade of the Troubles in Northern Ireland, which was a conflict that dominated Northern Irish daily life for decades. However, from 1981 onwards the population grows by 70,000 to 12,000 every ten years, surpassing it's pre-famine level in the 1990s.

The fertility rate of a country is the average number of children that women from that country would have throughout their reproductive years. In the United Kingdom in 1800, the average woman of childbearing age would have five children over the course of their lifetime. Over the next 35 years the fertility rate was quite sporadic, rising to over 5.5 in the 1810s and 1820s, then dropping to 4.9 by 1835. This was during and after the Napoleonic Wars and the War of 1812 with the US, which was a time of increased industrialization, economic depression and high unemployment after the war. As things became more stable, and the 'Pax Britannica' (a period of relative, international peace and economic prosperity for the British Empire) came into full effect, the fertility rate plateaued until 1880, before dropping gradually until the First World War. The fertility rate then jumped from 2.6 to 3.1 children per woman between 1915 and 1920, as many men returned from the war. It then resumed it's previous trajectory in the interwar years, before increasing yet again after the war (albeit, for a much longer time than after WWI), in what is known as the 'Baby Boom'. Like the US, the Baby Boom lasted until around 1980, where it then fell to 1.7 children per woman, and it has remained around this number (between 1.66 and 1.87) since then.