The world's population first reached one billion people in 1805, and reached eight billion in 2022, and will peak at almost 10.2 billion by the end of the century. Although it took thousands of years to reach one billion people, it did so at the beginning of a phenomenon known as the demographic transition; from this point onwards, population growth has skyrocketed, and since the 1960s the population has increased by one billion people every 12 to 15 years. The demographic transition sees a sharp drop in mortality due to factors such as vaccination, sanitation, and improved food supply; the population boom that follows is due to increased survival rates among children and higher life expectancy among the general population; and fertility then drops in response to this population growth. Regional differences The demographic transition is a global phenomenon, but it has taken place at different times across the world. The industrialized countries of Europe and North America were the first to go through this process, followed by some states in the Western Pacific. Latin America's population then began growing at the turn of the 20th century, but the most significant period of global population growth occurred as Asia progressed in the late-1900s. As of the early 21st century, almost two-thirds of the world's population lives in Asia, although this is set to change significantly in the coming decades. Future growth The growth of Africa's population, particularly in Sub-Saharan Africa, will have the largest impact on global demographics in this century. From 2000 to 2100, it is expected that Africa's population will have increased by a factor of almost five. It overtook Europe in size in the late 1990s, and overtook the Americas a few years later. In contrast to Africa, Europe's population is now in decline, as birth rates are consistently below death rates in many countries, especially in the south and east, resulting in natural population decline. Similarly, the population of the Americas and Asia are expected to go into decline in the second half of this century, and only Oceania's population will still be growing alongside Africa. By 2100, the world's population will have over three billion more than today, with the vast majority of this concentrated in Africa. Demographers predict that climate change is exacerbating many of the challenges that currently hinder progress in Africa, such as political and food instability; if Africa's transition is prolonged, then it may result in further population growth that would place a strain on the region's resources, however, curbing this growth earlier would alleviate some of the pressure created by climate change.

In 1938, the year before the outbreak of the Second world War, the countries with the largest populations were China, the Soviet Union, and the United States, although the United Kingdom had the largest overall population when it's colonies, dominions, and metropole are combined. Alongside France, these were the five Allied "Great Powers" that emerged victorious from the Second World War. The Axis Powers in the war were led by Germany and Japan in their respective theaters, and their smaller populations were decisive factors in their defeat. Manpower as a resource In the context of the Second World War, a country or territory's population played a vital role in its ability to wage war on such a large scale. Not only were armies able to call upon their people to fight in the war and replenish their forces, but war economies were also dependent on their workforce being able to meet the agricultural, manufacturing, and logistical demands of the war. For the Axis powers, invasions and the annexation of territories were often motivated by the fact that it granted access to valuable resources that would further their own war effort - millions of people living in occupied territories were then forced to gather these resources, or forcibly transported to work in manufacturing in other Axis territories. Similarly, colonial powers were able to use resources taken from their territories to supply their armies, however this often had devastating consequences for the regions from which food was redirected, contributing to numerous food shortages and famines across Africa, Asia, and Europe. Men from annexed or colonized territories were also used in the armies of the war's Great Powers, and in the Axis armies especially. This meant that soldiers often fought alongside their former-enemies. Aftermath The Second World War was the costliest in human history, resulting in the deaths of between 70 and 85 million people. Due to the turmoil and destruction of the war, accurate records for death tolls generally do not exist, therefore pre-war populations (in combination with other statistics), are used to estimate death tolls. The Soviet Union is believed to have lost the largest amount of people during the war, suffering approximately 24 million fatalities by 1945, followed by China at around 20 million people. The Soviet death toll is equal to approximately 14 percent of its pre-war population - the countries with the highest relative death tolls in the war are found in Eastern Europe, due to the intensity of the conflict and the systematic genocide committed in the region during the war.

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.

United States Population: All Ages data was reported at 325,719.000 Person th in 2017. This records an increase from the previous number of 323,406.000 Person th for 2016. United States Population: All Ages data is updated yearly, averaging 176,356.000 Person th from Jun 1900 (Median) to 2017, with 118 observations. The data reached an all-time high of 325,719.000 Person th in 2017 and a record low of 76,094.000 Person th in 1900. United States Population: All Ages data remains active status in CEIC and is reported by US Census Bureau. The data is categorized under Global Database’s United States – Table US.G002: Population by Age. Series Remarks Population data for the years 1900 to 1949 exclude the population residing in Alaska and Hawaii. Population data for the years 1940 to 1979 cover the resident population plus Armed Forces overseas. Population data for all other years cover only the resident population.

Peru Census Population: Lima data was reported at 9,485,405.000 Person in 2017. This records an increase from the previous number of 8,445,211.000 Person for 2007. Peru Census Population: Lima data is updated yearly, averaging 4,745,877.000 Person from Jun 1940 (Median) to 2017, with 7 observations. The data reached an all-time high of 9,485,405.000 Person in 2017 and a record low of 828,298.000 Person in 1940. Peru Census Population: Lima data remains active status in CEIC and is reported by National Institute of Statistics and Informatics. The data is categorized under Global Database’s Peru – Table PE.G003: Population: Census by Department.

In the past four centuries, the population of the Thirteen Colonies and United States of America has grown from a recorded 350 people around the Jamestown colony in Virginia in 1610, to an estimated 346 million in 2025. While the fertility rate has now dropped well below replacement level, and the population is on track to go into a natural decline in the 2040s, projected high net immigration rates mean the population will continue growing well into the next century, crossing the 400 million mark in the 2070s. Indigenous population Early population figures for the Thirteen Colonies and United States come with certain caveats. Official records excluded the indigenous population, and they generally remained excluded until the late 1800s. In 1500, in the first decade of European colonization of the Americas, the native population living within the modern U.S. borders was believed to be around 1.9 million people. The spread of Old World diseases, such as smallpox, measles, and influenza, to biologically defenseless populations in the New World then wreaked havoc across the continent, often wiping out large portions of the population in areas that had not yet made contact with Europeans. By the time of Jamestown's founding in 1607, it is believed the native population within current U.S. borders had dropped by almost 60 percent. As the U.S. expanded, indigenous populations were largely still excluded from population figures as they were driven westward, however taxpaying Natives were included in the census from 1870 to 1890, before all were included thereafter. It should be noted that estimates for indigenous populations in the Americas vary significantly by source and time period. Migration and expansion fuels population growth The arrival of European settlers and African slaves was the key driver of population growth in North America in the 17th century. Settlers from Britain were the dominant group in the Thirteen Colonies, before settlers from elsewhere in Europe, particularly Germany and Ireland, made a large impact in the mid-19th century. By the end of the 19th 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. It is also estimated that almost 400,000 African slaves were transported directly across the Atlantic to mainland North America between 1500 and 1866 (although the importation of slaves was abolished in 1808). Blacks made up a much larger share of the population before slavery's abolition. Twentieth and twenty-first century The U.S. population has grown steadily since 1900, reaching one hundred million in the 1910s, two hundred million in the 1960s, and three hundred million in 2007. Since WWII, the U.S. has established itself as the world's foremost superpower, with the world's largest economy, and most powerful military. This growth in prosperity has been accompanied by increases in living standards, particularly through medical advances, infrastructure improvements, clean water accessibility. These have all contributed to higher infant and child survival rates, as well as an increase in life expectancy (doubling from roughly 40 to 80 years in the past 150 years), which have also played a large part in population growth. As fertility rates decline and increases in life expectancy slows, migration remains the largest factor in population growth. Since the 1960s, Latin America has now become the most common origin for migrants in the U.S., while immigration rates from Asia have also increased significantly. It remains to be seen how immigration restrictions of the current administration affect long-term population projections for the United States.

Peru Census Population: Urban: Junín data was reported at 884,928.000 Person in 2017. This records an increase from the previous number of 752,337.000 Person for 2007. Peru Census Population: Urban: Junín data is updated yearly, averaging 510,662.000 Person from Jun 1940 (Median) to 2017, with 7 observations. The data reached an all-time high of 884,928.000 Person in 2017 and a record low of 137,776.000 Person in 1940. Peru Census Population: Urban: Junín data remains active status in CEIC and is reported by National Institute of Statistics and Informatics. The data is categorized under Global Database’s Peru – Table PE.G003: Population: Census by Department.

Hungary Population: Female data was reported at 5,122,270.000 Person in 2017. This records a decrease from the previous number of 5,141,966.000 Person for 2016. Hungary Population: Female data is updated yearly, averaging 5,271,882.000 Person from Dec 1940 (Median) to 2017, with 24 observations. The data reached an all-time high of 5,520,754.000 Person in 1979 and a record low of 4,755,199.000 Person in 1940. Hungary Population: Female data remains active status in CEIC and is reported by Hungarian Central Statistical Office. The data is categorized under Global Database’s Hungary – Table HU.G002: Population: Annual.

Brazil Population Census: Urban: Male data was reported at 77,710,179.000 Person in 2010. This records an increase from the previous number of 66,882,993.000 Person for 2000. Brazil Population Census: Urban: Male data is updated yearly, averaging 32,238,393.500 Person from Jul 1940 (Median) to 2010, with 8 observations. The data reached an all-time high of 77,710,179.000 Person in 2010 and a record low of 6,164,473.000 Person in 1940. Brazil Population Census: Urban: Male data remains active status in CEIC and is reported by Brazilian Institute of Geography and Statistics. The data is categorized under Brazil Premium Database’s Socio and Demographic – Table BR.GAC001: Population Census.

Population Census: Central West: Mato Grosso do Sul data was reported at 2,757,013.000 Person in 2022. This records an increase from the previous number of 2,449,024.000 Person for 2010. Population Census: Central West: Mato Grosso do Sul data is updated yearly, averaging 1,778,741.000 Person from Jul 1940 (Median) to 2022, with 11 observations. The data reached an all-time high of 2,757,013.000 Person in 2022 and a record low of 238,640.000 Person in 1940. Population Census: Central West: Mato Grosso do Sul data remains active status in CEIC and is reported by Brazilian Institute of Geography and Statistics. The data is categorized under Global Database’s Brazil – Table BR.GAC008: Population Census: by State.

Brazil Population Census: Rural: Male data was reported at 15,696,811.000 Person in 2010. This records a decrease from the previous number of 16,693,022.000 Person for 2000. Brazil Population Census: Rural: Male data is updated yearly, averaging 17,772,352.000 Person from Jul 1940 (Median) to 2010, with 8 observations. The data reached an all-time high of 21,089,403.000 Person in 1970 and a record low of 14,449,615.000 Person in 1940. Brazil Population Census: Rural: Male data remains active status in CEIC and is reported by Brazilian Institute of Geography and Statistics. The data is categorized under Brazil Premium Database’s Socio and Demographic – Table BR.GAC001: Population Census.

Peru Census Population: Urban: Lima data was reported at 9,324,796.000 Person in 2017. This records an increase from the previous number of 8,216,143.000 Person for 2007. Peru Census Population: Urban: Lima data is updated yearly, averaging 4,542,911.000 Person from Jun 1940 (Median) to 2017, with 7 observations. The data reached an all-time high of 9,324,796.000 Person in 2017 and a record low of 630,173.000 Person in 1940. Peru Census Population: Urban: Lima data remains active status in CEIC and is reported by National Institute of Statistics and Informatics. The data is categorized under Global Database’s Peru – Table PE.G003: Population: Census by Department.

The global population has grown rapidly since 1950, from 2.5 billion to over eight billion in 2023. The age distribution shows that the number of people within all age groups increased over the period, with the two youngest age groups being the largest in 2023. Population growth driven by development in Asia The increasing global population is explained by economic development and a coinciding improvement in living conditions in several parts of the world, particularly in Asia. Improvements in sanitary conditions, the rollout of vaccination programs, and better medical treatment brought down death rates around the world. China saw fast economic development from the early 1980s to the late 2010s, going hand in hand with a rapidly increasing population. Furthermore, the population of India has grown rapidly since it gained independence from the British Empire in the late 1940s, now being the largest in the world. Most of the future population growth will happen in Africa The global population is forecast to continue to increase over the coming decades, set to reach over 10 billion people by 2060. Most of this increase is projected to occur on the African continent, as many African countries are expected to experience an improvement in living standards. In 2022, over 40 percent of the population in Sub-Saharan Africa was below 15 years old.

Brazil Population Census: Urban: Female data was reported at 83,215,625.000 Person in 2010. This records an increase from the previous number of 71,070,966.000 Person for 2000. Brazil Population Census: Urban: Female data is updated yearly, averaging 34,028,900.000 Person from Jul 1940 (Median) to 2010, with 8 observations. The data reached an all-time high of 83,215,625.000 Person in 2010 and a record low of 6,715,709.000 Person in 1940. Brazil Population Census: Urban: Female data remains active status in CEIC and is reported by Brazilian Institute of Geography and Statistics. The data is categorized under Brazil Premium Database’s Socio and Demographic – Table BR.GAC001: Population Census.

Brazil Population Census: Rural: Female data was reported at 14,133,184.000 Person in 2010. This records a decrease from the previous number of 15,152,189.000 Person for 2000. Brazil Population Census: Rural: Female data is updated yearly, averaging 16,725,643.500 Person from Jul 1940 (Median) to 2010, with 8 observations. The data reached an all-time high of 19,948,183.000 Person in 1970 and a record low of 13,906,518.000 Person in 1940. Brazil Population Census: Rural: Female data remains active status in CEIC and is reported by Brazilian Institute of Geography and Statistics. The data is categorized under Brazil Premium Database’s Socio and Demographic – Table BR.GAC001: Population Census.

Peru Census Population: Ica data was reported at 850,765.000 Person in 2017. This records an increase from the previous number of 711,932.000 Person for 2007. Peru Census Population: Ica data is updated yearly, averaging 433,897.000 Person from Jun 1940 (Median) to 2017, with 7 observations. The data reached an all-time high of 850,765.000 Person in 2017 and a record low of 140,898.000 Person in 1940. Peru Census Population: Ica data remains active status in CEIC and is reported by National Institute of Statistics and Informatics. The data is categorized under Global Database’s Peru – Table PE.G003: Population: Census by Department.

In 2024, the population of the United Kingdom reached 69.3 million, compared with 68.5 million in 2023. The UK population has more than doubled since 1871 when just under 31.5 million lived in the UK and has grown by around 10.4 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 58.6 million people in 2024. By comparison, Scotland, Wales, and Northern Ireland had populations of 5.5 million, 3.2 million, and 1.9 million, respectively. Within England, South East England had the largest population, at over 9.6 million, followed by the UK's vast capital city of London, at almost 9.1 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.

Peru Census Population: Amazonas data was reported at 379,384.000 Person in 2017. This records an increase from the previous number of 375,993.000 Person for 2007. Peru Census Population: Amazonas data is updated yearly, averaging 254,560.000 Person from Jun 1940 (Median) to 2017, with 7 observations. The data reached an all-time high of 379,384.000 Person in 2017 and a record low of 65,137.000 Person in 1940. Peru Census Population: Amazonas data remains active status in CEIC and is reported by National Institute of Statistics and Informatics. The data is categorized under Global Database’s Peru – Table PE.G003: Population: Census by Department.

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.

BackgroundIt is well known that asthma prevalence has been increasing all over the world in the last decades. However, few data are available on temporal trends of incidence and remission of asthma.ObjectiveTo evaluate the rates of asthma incidence and remission in Italy from 1940 to 2010.MethodsThe subjects were randomly sampled from the general Italian population between 1991 and 2010 in the three population-based multicentre studies: ECRHS, ISAYA, and GEIRD. Individual information on the history of asthma (age at onset, age at the last attack, use of drugs for asthma control, co-presence of hay-fever) was collected on 35,495 subjects aged 20–84 and born between 1925–1989. Temporal changes in rates of asthma incidence and remission in relation to age, birth cohort and calendar period (APC) were modelled using Poisson regression and APC models.ResultsThe average yearly rate of asthma incidence was 2.6/1000 (3,297 new cases among 1,263,885 person-years). The incidence rates have been linearly increasing, with a percentage increase of +3.9% (95%CI: 3.1–4.5), from 1940 up to the year 1995, when the rates begun to level off. The stabilization of asthma incidence was mainly due to a decrease in the rates of atopic asthma after 1995, while non-atopic asthma has continued to increase. The overall rate of remission was 43.2/1000person-years, and it did not vary significantly across generations, but was associated with atopy, age at asthma onset and duration of the disease.ConclusionsAfter 50 years of a continuous upward trend, the rates of asthma incidence underwent a substantial stabilization in the late 90s. Despite remarkable improvements in the treatment of asthma, the rate of remission did not change significantly in the last seventy years. Some caveats are required in interpreting our results, given that our estimates are based on self-reported events that could be affected by the recall bias.