In the United States, the crude birth rate in 1800 was 48.3 live births per thousand people, meaning that 4.8 percent of the population had been born in that year. Between 1815 and 1825 the crude birth rate jumped from 46.5 to 54.7 (possibly due to Florida becoming a part of the US, but this is unclear), but from this point until the Second World War the crude birth rate dropped gradually, reaching 19.2 in 1935. Through the 1940s, 50s and 60s the US experienced it's baby boom, and the birth rate reached 24.1 in 1955, before dropping again until 1980. From the 1980s until today the birth rate's decline has slowed, and is expected to reach twelve in 2020, meaning that just over 1 percent of the population will be born in 2020.

Among nations of the UK, Northern Ireland had the highest number of live births per 1,000 in 2021, at 11.6, followed by England at 10.5, Wales at 9.3, and Scotland at 8.7. The crude birth has fallen for all nations of the UK when compared with 1971, while Northern Ireland has consistently had the highest number of live births per 1,000 people. Long-term birth trends After reaching a postwar peak of 18.8 births per 1,000 people, the UK's crude birth rate has declined considerably, falling to a low of just 11 births per 1,000 people in 2020. In that year, there were just 681,560 live births, compared with over one million in 1964. Additionally, the average age of mothers in the UK has been steadily increasing since the mid-1970s. In 1975, for example, the average age at which mothers gave birth was 26.4 years, compared with 30.9 in 2021. Millennials overtake Boomers as largest generation Due to the large number of births that happened in the years following the Second World War, the generation born during this time were called Baby Boomers, and until 2020 were the largest generation in the UK. Since that year, the Millennial generation, born between 1981 and 1996 have been the largest generational cohort. In 2022, there were approximately 14.48 million Millennials, 14.14 million Generation X members (born between 1965 and 1980) and around 13.8 million Baby Boomers. Generation Z, the generation immediately after Millennials, numbered approximately 12.9 million in 2022.

The fertility rate of a country is the average number of children that women from that country will have throughout their reproductive years. In Germany in 1800, the average woman of childbearing age would have 5.4 children over the course of their lifetime. It remained around this number until the late 1820s, when it then dropped to just under five, which was a long-term effect of the Napoleonic Period in Europe. From this point until the end of the nineteenth century, Germany's fertility rate was rather sporadic, reaching it's lowest point in 1855 with an average of 4.6 births per woman, and it's highest point in 1875 (just after the foundation of the German Empire in 1871), with an average of 5.4 live births per woman. From the beginning of the twentieth century until the end of the Second World War, Germany's fertility rate dropped from around 5 children per woman in 1900, to 1.9 in 1945. The only time where the fertility rate increased was in the inter-war years. Like other countries heavily involved in the Second World War, Germany (both East and West) experienced a Baby Boom from the late 1940s to the late 1960s, however it then dropped to it's lowest point of just 1.3 children per woman by 1995, shortly after the re-unification of Germany. In recent years, Germany's fertility rate has gradually been increasing again, and is expected to reach 1.6 in 2020, its highest rate in over forty years.

The fertility rate of a country is the average number of children that women from that country will have throughout their reproductive years. In the United States in 1800, the average woman of childbearing age would have seven children over the course of their lifetime. As factors such as technology, hygiene, medicine and education improved, women were having fewer children than before, reaching just two children per woman in 1940. This changed quite dramatically in the aftermath of the Second World War, rising sharply to over 3.5 children per woman in 1960 (children born between 1946 and 1964 are nowadays known as the 'Baby Boomer' generation, and they make up roughly twenty percent of todays US population). Due to the end of the baby boom and increased access to contraception, fertility reached it's lowest point in the US in 1980, where it was just 1.77. It did however rise to over two children per woman between 1995 and 2010, although it is expected to drop again by 2020, to just 1.78.

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.

The fertility rate of a country is the average number of children that women from that country will have throughout their reproductive years. From 1800 until today, Poland's fertility rate has gradually declined, however it was very sporadic along the way. Poland's fertility rate reached it's highest point in the early 1860s, where it was 6.4 children per woman. Between 1795 and the end of the First World War there was no official country of Poland, and this is a tumultuous time in the area's history, and many different factors would have affected the fertility rate. In the Second World War, Poland's lost a higher percentage of people than any other nation in the world, and the fertility rate dropped to just over 3 children per woman during this time. Poland did experience a brief 'baby boom' during the two decades after the war, before the rate fell to it's lowest point ever in 2005, where it was below 1.3 children per woman, and this number is expected to rise slightly by 2020, to 1.4.

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.

In France, the crude birth rate in 1800 was 29.4 live births per thousand people, meaning that 2.9 percent of the population had been born in that year. In the first half of the nineteenth century France's crude birth rate dropped from it's highest recorded level of 29.4 in 1800, to 21.9 by 1850. In the second half of the 1800s the crude birth rate rose again, to 25.5 in 1875, as the Second Republic and Second Empire were established, which was a time of economic prosperity and the modernization of the country. From then until 1910 there was a gradual decline, until the First World War caused a huge decline, resulting in a record low crude birth rate of 13.3 by 1920 (the figures for individual years fell even lower than this). The figure then bounced back in the early 1920s, before then falling again until the Second World War. After the war, France experienced a baby boom, where the crude birth rate reached 22.2, before it dropped again until the 1980s, and since then it has declined slowly. The crude birth rate of France is expected to reach a new, record low of 11.2 in 2020.

In China, the crude birth rate in 1930 was just under 39 live births per thousand people, meaning that 3.9 percent of the population had been born in that year. The crude birth rate dropped gradually over the next fifteen years, however it then rose to it's highest recorded figure by 1955. Between 1945 and 1950, the Second World War ended and the Chinese Civil War was finally coming to an end, and during this time the crude birth rate rose to almost 47 births per thousand in individual years. The crude birth rate dropped again in the late 1950s, as Chairman Mao's 'Great Leap Forward' failed to industrialize the nation, and resulted in a famine which killed an estimated 45 million people. The 1960s saw some recovery, where the figures rose from 36.4 to 39.5 births per thousand in this decade, however two-child and one-child policies were introduced in the 1970s and 80s, in an attempt to slow China's rapidly growing population. These measures led to the decline of the birth rate, dropping below fifteen births per thousand at the turn of the millennium. From 2000 until now the decline of China's crude birth rate has slowed, falling by just 2.8 births per thousand over the past twenty years, and it is expected to be just below twelve in 2020.

The fertility rate of a country is the average number of children that women from that country would have throughout their reproductive years. In France in 1800, the average woman of childbearing age would have 4.4 children over the course of their lifetime. The beginning of the nineteenth century was a tumultuous time in France's history, involving France's revolutionary period, as well as the Napoleonic Empire. In the first decade of the 1800s, the fertility rate dropped by 0.4, before dropping more slowly, by another 0.5 between 1810 and 1850. The fertility growth rate fluctuated slightly in the late 1800s, before dropping drastically in the early twentieth century, falling from an average of 3 children per woman to less than 1.7 in 1920. France's fertility rate reached this point as a result of the First World War, and the influenza epidemic (known as the Spanish Flu) that followed. The interwar period saw a slight increase in fertility rate, before it fell again in the Second World War. Similarly to other major European countries after the war, France experienced a baby boom in the two decades following the war, before dropping again into the 1980s. The fertility rate reached it's lowest point in the post-war period, falling to 1.7 in 1995, before increasing in more recent years.

In 2024, the birth rate in France reached its lowest level since 1982. From 1982 to 2019, the birth rate in France has been fluctuating between more than 11 births and almost 14 births for 1,000 inhabitants. For the first time in this period, the birth rate fell below 11 in 2020. The highest birth rate in France during this period was recorded in 1982. That year there were 14.8 births per 1,000 inhabitants. Since then, the birth rate in the country keeps decreasing. If France keeps being one of the European countries with the highest fertility rate, it is still been impacted by the decline in the birth rate that affects most Western countries. A Declining birth rate Birth rate is the ration between the annual number of live births and the average total population over that year. In 2023, there were 640,000 live births in France, while the French population amounted to 68 million people. The average number of children born per women went from 2.03 in 2010, down to 1.66 in 2023. Births in France With a crude birth rate of 10.9 births per 1,000 inhabitants in 2020, France still has one of the highest birth rates in Europe. The percentage of children born out-of-wedlock in France has been rising since the nineties, reaching 65.2 percent in 2022. Another change can be seen in the average age at childbirth among French women. In 2022, most of women in France were aged 31.1 years old at childbirth, compared to 28.8 years old in 1994.

The fertility rate of a country is the average number of children that women from that country will have throughout their reproductive years. From 1840 until 1910, Russia's fertility rate was relatively consistent, remaining between 6.7 and 7.4 children per woman during this time. Between 1910 and 1920, the fertility rate drops sharply as a result of the First World War and Russian Revolution (for individual years of WWI, the fertility rate dropped as low as 3.4). From 1920 to 1930 the fertility rate returns above 6 again, however a gradual decline then begins, and by the end of the Second World War, the Russian segment of the Soviet Union's fertility rate was below 2. The population experienced a relatively small 'baby boom' in the two decades following the war, but then the fertility rate dropped again, most sharply between 1990 and 1995 at the end of the Soviet Union's reign. Russia's fertility rate reached its lowest point in 2000 when it fell to just 1.25 children per woman, but in the past two decades it has risen again, and is expected to reach 1.8 in 2020.

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 Italy, the crude birth rate in 1850 was 38.4 live births per thousand people, meaning that 3.8 percent of the population had been born in that year. Apart from some slight fluctuation in the 1860s, between 1850 and the Second World War, Italy's crude birth rate decreased very gradually. 38.9 was the highest recorded figure in 1865, and it decreased to 27.1 in 1930. Over the next 35 years (including the Second World War and Italian Civil War) the birth rate fluctuated, but overall it dropped to 18.6, and then the decline fell consistently to 10.9 in 1985, where it then plateaued. In the 2000s, the crude birth rate did increase in the first decade, to 9.7 in 2010, before dropping again, and it is expected to fall to it's lowest level of 7.6 in 2020.

In 1900, the crude birth rate in South Korea was just under 42 births for every thousand people, meaning that approximately 4.2 percent of the population was born in that year. The crude birth rate would rise briefly in the 1930s, as Japanese investment would lead to economic growth on the peninsula, but would fall sharply in the 1940s, as the Second World War and the Korean War would result in two decades of significant socio-economic turmoil. While the crude birth rate would recover quickly after the end of the Korean War in 1953, a sharp decline in fertility beginning in the 1960s would see a corresponding fall in the crude birth rate lasting until the late 1980s, as South Korea would go through a rapid demographic transition and modernization. While the crude birth rate would briefly rise in the early 1990s, partially due to governmental restrictions on sex-selective abortion; the rate of decline would slow going into the 21st century. As a result, in 2020, it is estimated that South Korea has a birth rate of seven births for every thousand people, which is one of the lowest birth rates 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.

In Germany, the crude birth rate in 1800 was 38 live births per thousand people, meaning that 3.8 percent of the population had been born in that year. In the nineteenth century, Germany's crude birth rate fluctuated between 34 and 40 births per thousand people. Since the turn of the twentieth century however, the crude birth rate has been in decline, although there were a few periods where it did increase. These increases took place during periods of economic recovery, after both world wars, and after the Great Depression. The largest period of increase was after the Second World War, and lasted until the late 1960s, before decreasing to 10.3 in 1980, where it then plateaus between eight and eleven, and it is expected to be 9.4 births per thousand people in 2020.

The fertility rate of a country is the average number of children that women from that country will have throughout their reproductive years. From 1800 until 1865, Japan's fertility rate grew quite gradually, from 4.1 children per woman, to 4.8. From this point the fertility rate drops to 3.6 over the next ten years, as Japan became more industrialized. Towards the end of the nineteenth century, Japan's fertility rate grew again, and reached it's highest recorded point in the early 1920s, where it was 5.4 children per woman. Since this point it has been gradually decreasing until now, although it did experience slight increases after the Second World War, and in the early 1970s. In recent decades Japan's population has aged extensively, and today, Japan has the second oldest population and second highest life expectancy in the world (after Monaco). In contrast to this, Japan has a very low birth rate, and it's fertility rate is expected to fall below 1.4 children per woman in 2020.

In Japan, the crude birth rate in 1800 was 29.6 live births per thousand people, meaning that approximately three percent of the population had been born in that year. From 1800 to 1865, Japan's crude birth rate rose gradually to around 34 births per thousand people, before dropping relatively sharply to 25 over the next ten years. This was a time of great social and economic reform in Japan, as the country became increasingly urbanized and industrialized. Japan's crude birth rate reached it's highest recorded point in the early 1920s, where the number was almost 35 births per thousand people, and since then it has been decreasing gradually. There were two times in the twentieth century where Japan's crude birth rate increased, after the Second World War, and during the period of economic prosperity in the 1960s and 70s. Since 1975, Japan's crude birth rate has gradually decreased to it's lowest recorded rate ever, and is expected to be at just 7.5 births per thousand people in 2020, making it the second lowest in the world (behind Monaco).

The fertility rate of a country is the average number of children that women from that country will have throughout their reproductive years. In 1930, China's fertility rate was 5.5 children per woman, and this number then dropped to just under five over the next fifteen years, as China experienced a civil war and the Second World War. The fertility rate rose rather quickly after this to over 6.1 in 1955, before dropping again in the late 1950s, as Chairman Mao's 'Great Leap Forward' failed to industrialize the nation, and resulted in widespread famine that killed an estimated 45 million people. In the decade following this, China's fertility rate reached it's highest level in 1970, before the implementation of the two-child policy in the 1970s, and the one-child policy** in the 1980s, which radically changed the population structure. The fertility rate fell to an all time low in the early 2000s, where it was just 1.6 children per woman. However this number has increased to 1.7 today, and the two-child policy was reintroduced in 2016, replacing the one-child policy that had been effective for over 36 years.