From the mid-19th century until today, life expectancy at birth in the United States has roughly doubled, from 39.4 years in 1850 to 79.6 years in 2025. It is estimated that life expectancy in the U.S. began its upward trajectory in the 1880s, largely driven by the decline in infant and child mortality through factors such as vaccination programs, antibiotics, and other healthcare advancements. Improved food security and access to clean water, as well as general increases in living standards (such as better housing, education, and increased safety) also contributed to a rise in life expectancy across all age brackets. There were notable dips in life expectancy; with an eight year drop during the American Civil War in the 1860s, a seven year drop during the Spanish Flu empidemic in 1918, and a 2.5 year drop during the Covid-19 pandemic. There were also notable plateaus (and minor decreases) not due to major historical events, such as that of the 2010s, which has been attributed to a combination of factors such as unhealthy lifestyles, poor access to healthcare, poverty, and increased suicide rates, among others. However, despite the rate of progress slowing since the 1950s, most decades do see a general increase in the long term, and current UN projections predict that life expectancy at birth in the U.S. will increase by another nine years before the end of the century.

Life expectancy in the United Kingdom was below 39 years in the year 1765, and over the course of the next two and a half centuries, it is expected to have increased by more than double, to 81.1 by the year 2020. Although life expectancy has generally increased throughout the UK's history, there were several times where the rate deviated from its previous trajectory. These changes were the result of smallpox epidemics in the late eighteenth and early nineteenth centuries, new sanitary and medical advancements throughout time (such as compulsory vaccination), and the First world War and Spanish Flu epidemic in the 1910s.

Life expectancy in Germany was below 39 in the year 1875, and over the course of the next 145 years, it is expected to have increased to above 81 years in the year 2020. Although life expectancy has generally increased throughout Germany's history, there were several times where the rate deviated from its previous trajectory. The most notable changes were because of the First and Second World Wars, in the first half of the twentieth century.

In 1910, life expectancy from birth in the region of present-day Syria was estimated at 32 years. This figure would see little change until 1935, outside of a brief dip in the late 1910s as the 1918 Spanish Flu epidemic would spread across the area. Life expectancy then began rising sharply from the late 1930s onwards, as modernization programs implemented by French, British and, later, independent authorities saw mass vaccination campaigns and healthcare improvements which greatly reduced child mortality rates. This climb would continue throughout the rest of the 20th century, and as a result, by 2000, the average person born in Syria could expect to live to over the age of 72.

However, life expectancy would see a sudden fall with the beginning of the Syrian Civil War in 2011. After peaking at just over 74 years in 2010, life expectancy would fall to just under 70 years by 2015, as the country’s civil war would lead to an estimated half a million fatalities, as well as mass displacement and the exodus of refugees from the country. As the fighting has gradually decreased in intensity in recent years, life expectancy of Syria has risen slightly, and in 2020, the average person born in Syria can expect to live to just over 71 years on average; although there is a difference of over eleven years in life expectancy between male and females.

Life expectancy in Japan was 36.4 in the year 1860, and over the course of the next 160 years, it is expected to have increased to 84.4, which is the second highest in the world (after Monaco). Although life expectancy has generally increased throughout Japan's history, there were several times where the rate deviated from its previous trajectory. These changes were a result of the Spanish Flu in the 1910s, the Second World War in the 1940s, and the sharp increase was due to the high rate of industrialization and economic prosperity in Japan, in the mid-twentieth century.

Life expectancy in India was 25.4 in the year 1800, and over the course of the next 220 years, it has increased to almost 70. Between 1800 and 1920, life expectancy in India remained in the mid to low twenties, with the largest declines coming in the 1870s and 1910s; this was because of the Great Famine of 1876-1878, and the Spanish Flu Pandemic of 1918-1919, both of which were responsible for the deaths of up to six and seventeen million Indians respectively; as well as the presence of other endemic diseases in the region, such as smallpox. From 1920 onwards, India's life expectancy has consistently increased, but it is still below the global average.

PERIOD: 1935-1936. SOURCE: [Statistics and reports of major countries].

Life expectancy in China was just 32 in the year 1850, and over the course of the next 170 years, it is expected to more than double to 76.6 years in 2020. Between 1850 and 1950, finding reliable data proved difficult for anthropologists, however some events, such as the Taiping Rebellion and Dungan Revolt in the nineteenth century did reduce life expectancy by a few years, and also the Chinese Civil War and Second World War in the first half of the twentieth century. In the second half of the 1900s, Chinese life expectancy increased greatly, as the country became more industrialized and the standard of living increased.

Life expectancy in Sweden was 36 in the year 1765, and over the course of the next 255 years, it is expected to have increased to 82.6 by 2020. Although life expectancy has generally increased throughout Sweden's history, there was a lot of fluctuation around the turn of the nineteenth century due to The Napoleonic Wars and First Cholera Epidemic, and again in the 1910s due to the Spanish Flu Epidemic.

Life expectancy in Canada was just below forty in the year 1800, and over the course of the next 220 years, it is expected to have increased by more than double to 82.2 by the year 2020. Throughout this time, life expectancy in Canada progressed at a steady rate, with the most noticeable changes coming during the interwar period, where the rate of increase was affected by the Spanish Flu epidemic and both World Wars.

Life expectancy in France was below thirty in the late 1700s, but over the course of the next two and a half centuries it is expected to reach 82.5 by the year 2020. Although life expectancy has generally increased throughout France's history, there were several times where the rate deviated from its previous trajectory. The most noticeable changes were because of smallpox and influenza epidemics in the 1700s, medical advancements (such as vaccination and pasteurization) saw life expectancy increase in the 1800s, and then both World Wars and the epidemics that followed caused brief drops in the first half of the twentieth century.

Life expectancy in Poland was 35.9 in the year 1885, and over the course of the next 135 years, it is expected to have increased to 78.5 by the year 2020. Although life expectancy has generally increased throughout Poland's history, the most noticeable decline came in the 1940s as a result of the Second World War and Holocaust, which caused Poland's population to decline by about 17 percent, which was more than any other country.

Life expectancy in Russia was 29.6 in the year 1845, and over the course of the next 175 years, it is expected to have increased to 72.3 years by 2020. Generally speaking, Russian life expectancy has increased over this 175 year period, however events such as the World Wars, Russian Revolution and a series of famines caused fluctuations before the mid-twentieth century, where the rate fluctuated sporadically. Between 1945 and 1950, Russian life expectancy more than doubled in this five year period, and it then proceeded to increase until the 1970s, when it then began to fall again. Between 1970 and 2005, the number fell from 68.5 to 65, before it then grew again in more recent years.

At the beginning of the 1840s, life expectancy from birth in Ireland was just over 38 years. However, this figure would see a dramatic decline with the beginning of the Great Famine in 1845, and dropped below 21 years in the second half of the decade (in 1849 alone, life expectancy fell to just 14 years). The famine came as a result of a Europe-wide potato blight, which had a disproportionally devastating impact on the Irish population due to the dependency on potatoes (particularly in the south and east), and the prevalence of a single variety of potato on the island that allowed the blight to spread faster than in other areas of Europe. Additionally, authorities forcefully redirected much of the country's surplus grain to the British mainland, which exacerbated the situation. Within five years, mass starvation would contribute to the deaths of over one million people on the island, while a further one million would emigrate; this also created a legacy of emigration from Ireland, which saw the population continue to fall until the mid-1900s, and the total population of the island is still well below its pre-famine level of 8.5 million people.

Following the end of the Great Famine, life expectancy would begin to gradually increase in Ireland, as post-famine reforms would see improvements in the living standards of the country’s peasantry, most notably the Land Wars, a largely successful series of strikes, boycotts and protests aimed at reform of the country's agricultural land distribution, which began in the 1870s and lasted into the 20th century. As these reforms were implemented, life expectancy in Ireland would rise to more than fifty years by the turn of the century. While this rise would slow somewhat in the 1910s, due to the large number of Irish soldiers who fought in the First World War and the Spanish Flu pandemic, as well as the period of civil unrest leading up to the island's partition in 1921, life expectancy in Ireland would rise greatly in the 20th century. In the second half of the 20th century, Ireland's healthcare system and living standards developed similarly to the rest of Western Europe, and today, it is often ranks among the top countries globally in terms of human development, GDP and quality of healthcare. With these developments, the increase in life expectancy from birth in Ireland was relatively constant in the first century of independence, and in 2020 is estimated to be 82 years.

Life expectancy in Spain was below thirty in the year 1880, and over the course of the next 140 years, it is expected to have increased to 83.4 by the year 2020. Although life expectancy has generally increased throughout Spain's history, there were several times where the rate deviated from its previous trajectory. The most notable changes were a result of the global influenza epidemic of the 1910s, (called the 'Spanish Flu' as it received more press coverage in neutral Spain, during the First World War) and the Spanish Civil War two decades later.

Life expectancy in Switzerland was 38 years in the year 1875, and over the course of the next 145 years, it is expected to have increased to 83.6 by the year 2020. Although life expectancy has generally increased throughout Switzerland's history, it decreased once in this period. This decrease was a result of the global influenza pandemic (known as the Spanish Flu) that spread across the world in the late 1910s.

Life expectancy in Australia was just below 35 in the year 1870, and over the course of the next 150 years, it is expected to have increased to 83.2 by the year 2020. Although life expectancy has generally increased throughout Australia's history, there were several times where the rate deviated from its previous trajectory. the most noticeable changes were between 1890 and 1920. This period included Australia's Independence movement, the implementation of the 'White Australia' policy, the First World War and Spanish Flu epidemic, all of which impacted the demographics of Australia.

Life expectancy in New Zealand was just over 34 in the year 1870, and over the course of the next 150 years, it is expected to have increased to just over 82 by the year 2020. Although life expectancy has generally increased along a gradual curve throughout New Zealand's history, there was a slight dip in the late 1910s, as a result of the First World War and following influenza epidemic. Apart from this, there were no anomalies that reduced life expectancy throughout this 150 year period.

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

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

The fertility rate of a country is the average number of children that women from that country will have throughout their reproductive years. In 1800, Australian women of childbearing age would go on to have approximately 6.5 children on average over the course of their lifetime, and this number decreased gradually to just below five in the early 1850s. Over the next ten years the fertility rate increased to 5.7 children per woman, as an influx of migrants arrived on the continent during the Australian gold rushes, however the fertility rate dropped from 1860 until 1935, when it was then just 2.2 children per woman, although there was a small baby boom after the First World War. Australia's fertility rate did rise during the global 'Baby Boom' after the Second World War, reaching 3.4 in the 1960s, but it then dropped to two children per woman in 1980, and it has plateaued just under this number until today.