Globally, about 25 percent of the population is under 15 years of age and 10 percent is over 65 years of age. Africa has the youngest population worldwide. In Sub-Saharan Africa, more than 40 percent of the population is below 15 years, and only three percent are above 65, indicating the low life expectancy in several of the countries. In Europe, on the other hand, a higher share of the population is above 65 years than the population under 15 years. Fertility rates The high share of children and youth in Africa is connected to the high fertility rates on the continent. For instance, South Sudan and Niger have the highest population growth rates globally. However, about 50 percent of the world’s population live in countries with low fertility, where women have less than 2.1 children. Some countries in Europe, like Latvia and Lithuania, have experienced a population decline of one percent, and in the Cook Islands, it is even above two percent. In Europe, the majority of the population was previously working-aged adults with few dependents, but this trend is expected to reverse soon, and it is predicted that by 2050, the older population will outnumber the young in many developed countries. Growing global population As of 2025, there are 8.1 billion people living on the planet, and this is expected to reach more than nine billion before 2040. Moreover, the global population is expected to reach 10 billions around 2060, before slowing and then even falling slightly by 2100. As the population growth rates indicate, a significant share of the population increase will happen in Africa.

According to latest figures, the Chinese population decreased by 1.39 million to around 1.408 billion people in 2024. After decades of rapid growth, China arrived at the turning point of its demographic development in 2022, which was earlier than expected. The annual population decrease is estimated to remain at moderate levels until around 2030 but to accelerate thereafter. Population development in China China had for a long time been the country with the largest population worldwide, but according to UN estimates, it has been overtaken by India in 2023. As the population in India is still growing, the country is very likely to remain being home of the largest population on earth in the near future. Due to several mechanisms put into place by the Chinese government as well as changing circumstances in the working and social environment of the Chinese people, population growth has subsided over the past decades, displaying an annual population growth rate of -0.1 percent in 2024. Nevertheless, compared to the world population in total, China held a share of about 17 percent of the overall global population in 2024. China's aging population In terms of demographic developments, the birth control efforts of the Chinese government had considerable effects on the demographic pyramid in China. Upon closer examination of the age distribution, a clear trend of an aging population becomes visible. In order to curb the negative effects of an aging population, the Chinese government abolished the one-child policy in 2015, which had been in effect since 1979, and introduced a three-child policy in May 2021. However, many Chinese parents nowadays are reluctant to have a second or third child, as is the case in most of the developed countries in the world. The number of births in China varied in the years following the abolishment of the one-child policy, but did not increase considerably. Among the reasons most prominent for parents not having more children are the rising living costs and costs for child care, growing work pressure, a growing trend towards self-realization and individualism, and changing social behaviors.

In 2023, the population density of Vietnam was around 303 people per square kilometer of land area. In that year, Vietnam's total population reached approximately 100.3 million. The country is among those with the highest population density in the Asia Pacific region, ranking 11th in 2020. Population density in Vietnam In comparison, Vietnam’s population density is roughly twice as much as China and Indonesia. The average population density in the world is at 59 inhabitants per square kilometer. The largest population within the country can be found in the Red River Delta and the Mekong River Delta. The most populated city is Ho Chi Minh City with roughly nine million inhabitants. Population growth in Vietnam Vietnam’s total population was forecast to surpass 100 million by 2050. Traditionally, Vietnamese families had an average of six children, while today, the birth rate is at two children per woman. This is due to an improving economy and higher living standards. In 2020, the population growth in Vietnam reached 0.90 percent, down from about three percent in the 1960s.

In 2023, Washington, D.C. had the highest population density in the United States, with 11,130.69 people per square mile. As a whole, there were about 94.83 residents per square mile in the U.S., and Alaska was the state with the lowest population density, with 1.29 residents per square mile. The problem of population density Simply put, population density is the population of a country divided by the area of the country. While this can be an interesting measure of how many people live in a country and how large the country is, it does not account for the degree of urbanization, or the share of people who live in urban centers. For example, Russia is the largest country in the world and has a comparatively low population, so its population density is very low. However, much of the country is uninhabited, so cities in Russia are much more densely populated than the rest of the country. Urbanization in the United States While the United States is not very densely populated compared to other countries, its population density has increased significantly over the past few decades. The degree of urbanization has also increased, and well over half of the population lives in urban centers.

Senior citizens are the fastest growing demographic in the world. Amid an intensification of digitalisation across every sector, evidence suggests older people are slow to adopt and use many online tools and services. Moreover, despite studies showing differences in the online behaviour of older people compared to the rest of the population, established models specifically dedicated to explaining their behaviour have remained limited. Therefore, based on components of UTAUT, we propose a new conceptual model that specifically focuses on senior citizens. We introduce four new constructs: health needs, place of settlement (rural/urban), perceived trust, and perceived risk. Data were collected from 320 seniors in Russia and a structural equation modelling was used for data analysis. With a cumulative variance of 86%, the test and validation results demonstrate that our proposed model provides a better explanation of older people’s online shopping behaviour than the original UTAUT model. This model provides an important framework for future studies on the digital shopping behaviours of seniors.

Estimated number of persons on July 1, by 5-year age groups and gender, and median age, for Canada, provinces and territories.

This statistic shows the age structure in Brazil from 2013 to 2023. In 2023 about 19.94 percent of Brazil's total population were aged 0 to 14 years. Population of Brazil Brazil is the fifth largest country in the world by area and population and the largest in both South America and the Latin American region. With a total population of more than 200 million inhabitants in 2013, Brazil also ranks fifth in terms of population numbers. Brazil is a founding member of the United Nations, the G20, CPLP, and a member of the BRIC countries. BRIC is an acronym for Brazil, Russia, India, and China, the four major emerging market countries. The largest cities in Brazil are São Paulo, Rio de Janeiro and Salvador. São Paulo alone reports over 11.1 million inhabitants. Due to a steady increase in the life expectancy in Brazil, the average age of the population has also rapidly increased. From 1950 until 2015, the average age of the population increased by an impressive 12 years; in 2015, the average age of the population in Brazil was reported to be around 31 years. As a result of the increasing average age, the percentage of people aged between 15 and 64 years has also increased: In 2013, about 68.4 percent of the population in Brazil was aged between 15 and 64 years.

Senior citizens are the fastest growing demographic in the world. Amid an intensification of digitalisation across every sector, evidence suggests older people are slow to adopt and use many online tools and services. Moreover, despite studies showing differences in the online behaviour of older people compared to the rest of the population, established models specifically dedicated to explaining their behaviour have remained limited. Therefore, based on components of UTAUT, we propose a new conceptual model that specifically focuses on senior citizens. We introduce four new constructs: health needs, place of settlement (rural/urban), perceived trust, and perceived risk. Data were collected from 320 seniors in Russia and a structural equation modelling was used for data analysis. With a cumulative variance of 86%, the test and validation results demonstrate that our proposed model provides a better explanation of older people’s online shopping behaviour than the original UTAUT model. This model provides an important framework for future studies on the digital shopping behaviours of seniors.

California was the state with the highest resident population in the United States in 2024, with 39.43 million people. Wyoming had the lowest population with about 590,000 residents. Living the American Dream Ever since the opening of the West in the United States, California has represented the American Dream for both Americans and immigrants to the U.S. The warm weather, appeal of Hollywood and Silicon Valley, as well as cities that stick in the imagination such as San Francisco and Los Angeles, help to encourage people to move to California. Californian demographics California is an extremely diverse state, as no one ethnicity is in the majority. Additionally, it has the highest percentage of foreign-born residents in the United States. By 2040, the population of California is expected to increase by almost 10 million residents, which goes to show that its appeal, both in reality and the imagination, is going nowhere fast.

Multiple species show significant trait shifts in response to urbanization. Yet, the impact of anthropogenic warming linked to the urban heat island effect is remarkably understudied. Additionally the relative contributions of phenotypic plasticity and genetic change underlying trait shifts in response to urbanization are poorly known. A common garden study with the water flea Daphnia magna revealed that both genetic differentiation in response to urbanization and phenotypic plasticity in response to higher rearing temperature (24 °C) induced significant parallel multivariate shifts in life history strategy along the slow-fast pace-of-life axis. Urban animals and animals reared at higher temperatures are characterized by fast maturation, early release of progeny, a smaller size at maturity, increased fecundity, and higher performance (given by maximal population growth rate r) compared to genotypes isolated from rural ponds and animals reared at lower temperatures respectively. Evolution in response to urbanization accounted for 30% of the total observed shift in life history and caused a significant change in mean trait values, while plasticity responses to experimental warming were unaltered between urban and rural populations. The total trait change achieved through both plasticity and evolution ranged from 8 to 56% depending on the trait. Our results provide clear evidence for evolution underlying an increase in pace-of-life of populations in response to urbanization. Given the pivotal role of Daphnia in aquatic ecosystems, this shift potentially feeds back to population structure, top-down control of algae, and food web dynamics in urban freshwater ecosystems. Additionally, we argue that adaptation to urban heat islands might render these populations pre-adapted in a context of future climate change.

Demographics characteristics of survey respondents.

New census data on age and sex show that as of May 15, 2001, the median age of Canada's population reached an all-time high of 37.6 years, an increase of 2.3 years from 35.3 in 1996. This was the biggest census-to-census increase in a century. Median age is the point where exactly one-half of the population is older, and the other half is younger. The nation's median age has been rising steadily since the end of the baby boom in 1966, when it was only 25.4 years. Nova Scotia and Quebec were the nation's oldest provinces, each with a median age of 38.8 years. Alberta was the youngest with a median age of 35.0. The group to increase at the fastest pace was that aged 80 and over. From 1991 to 2001, their numbers soared 41.2% to 932,000. The number of people aged 80 or over is expected to increase an additional 43% from 2001 to 2011, during which time it will surpass an estimated 1.3 million. At the same time, Canada has undergone a substantial decline in the number of children aged four and under. In 2001, the census counted 1.7 million children in this age group, down 11.0% from 1991, the result mostly of Canada's declining fertility rate. By 2011, this group may decline to an estimated 1.6 million.

Model fit measures of the structural equation model.

Reflects housing density depicting where humans and their structures meet or intermix with wildland fuels.Colorado is one of the fastest growing states in the Nation, with much of this growth occurring outside urban boundaries. This increase in population across the state will impact counties and communities that are located within the Wildland Urban Interface (WUI). The WUI is described as the area where structures and other human improvements meet and intermingle with undeveloped wildland or vegetative fuels. Population growth within the WUI substantially increases the risk from wildfire.The Wildland Urban Interface (WUI) layer reflects housing density depicting where humans and their structures meet or intermix with wildland fuels. In the past, conventional wildland-urban interface data sets, such as USFS SILVIS, have been used to reflect these concerns. However, USFS SILVIS and other existing data sources did not provide the level of detail needed by the Colorado State Forest Service and local fire protection agencies, particularly reflecting encroachment into urban core areas.The new WUI data set is derived using advanced modeling techniques based on the Where People Live (housing density) data set and 2021 LandScan USA population count data available from the Department of Homeland Security, HSIP data. WUI is simply a subset of the Where People Live data set. The primary difference is populated areas surrounded by sufficient non-burnable areas (i.e. interior urban areas) are removed from the Where People Live data set, as these areas are not expected to be directly impacted by a wildfire. Fringe urban areas, i.e. those on the edge of urban areas directly adjacent to burnable fuels are included in the WUI. Advanced encroachment algorithms were used to define these fringe areas.Data is modeled at a 20-meter grid cell resolution, which is consistent with other CO-WRA layers. The WUI classes are based on the number of houses per acre. Class breaks are based on densities well understood and commonly used for fire protection planning.

Direct influence of social factors using generalised linear model.

New census data on age and sex show that as of May 15, 2001, the median age of Canada's population reached an all-time high of 37.6 years, an increase of 2.3 years from 35.3 in 1996. This was the biggest census-to-census increase in a century. Median age is the point where exactly one-half of the population is older, and the other half is younger. The nation's median age has been rising steadily since the end of the baby boom in 1966, when it was only 25.4 years. Nova Scotia and Quebec were the nation's oldest provinces, each with a median age of 38.8 years. Alberta was the youngest with a median age of 35.0. The group to increase at the fastest pace was that aged 80 and over. From 1991 to 2001, their numbers soared 41.2% to 932,000. The number of people aged 80 or over is expected to increase an additional 43% from 2001 to 2011, during which time it will surpass an estimated 1.3 million. At the same time, Canada has undergone a substantial decline in the number of children aged four and under. In 2001, the census counted 1.7 million children in this age group, down 11.0% from 1991, the result mostly of Canada's declining fertility rate. By 2011, this group may decline to an estimated 1.6 million.

This statistic shows the age structure in Syria from 2013 to 2023. In 2023, about 30.34 percent of Syria's total population were aged 0 to 14 years. The shrinking population of Syria In the past, Syria’s population has been one of the fastest growing populations around the world. While the fertility rate is much lower now than it has been, in 2013, World Bank figures show a fertility rate of 3 children per woman. This rate is still relatively high, but the country’s historically expanding population has left the country with a large cohort of young people: Almost 40 percent of the Syrian population is under 14 years of age, with close to 60 percent of the population aged 15 to 64. This leaves around a meager 4 percent of Syrians who are over 65 years old. At present, the median age of the population is estimated to be around 23 years, which means half the population is under 23, leaving large numbers of young people at the mercy of the war that has plagued the country. As of October 2015, 12,517 children were reportedly killed in the fighting, with the number of unreported cases being presumably much higher than this. This dire situation has caused many people to flee the country and it is no surprise that the majority of them are young. Despite a high fertility rate, this mass emigration has significantly stalled population growth in the country, a trend which is expected to continue especially as an overwhelming majority of Syrians – 46 percent - stated they would leave the country if given the opportunity.

In 2024, 40-59-year-olds made up the largest age group in Germany, at around 22.3 million people. The most recent figures confirm that the next-largest age group was 65 years and older, at roughly 19 million. Aging population With the number of people belonging to older age groups visibly outstripping younger ones, in recent years it has become clear that Germany’s population is aging. In fact, figures on age structure in Germany depict a constant trend of a slowly increasing population share aged over 65 since 2012. Meanwhile, the share of population members aged 0 to 14 years has been falling, which was also reflected in the fluctuating national birth rate in recent years. A look at the future Germany’s current total population is around 83.6 million. While this number is predicted to increase, the same goes for the age group of 65 years and older. This means that the national population will continue to age.

Africa has the youngest population in the world. Among the 35 countries with the lowest median age worldwide, only three fall outside the continent. In 2023, the median age in Niger was 15.1 years, the youngest country. This means that at this age point, half of the population was younger and half older. A young population reflects several demographic characteristics of a country. For instance, together with a high population growth, life expectancy in Western Africa is low: this reached 57 years for men and 59 for women. Overall, Africa has the lowest life expectancy in the world.

Africa’s population is still growing Africa’s population growth can be linked to a high fertility rate along with a drop in death rates. Despite the fertility rate on the continent, following a constant declining trend, it remains far higher compared to all other regions worldwide. It was forecast to reach 4.12 children per woman, compared to a worldwide average of 2.31 children per woman in 2024. Furthermore, the crude death rate in Africa overall dropped, only increasing slightly during the coronavirus (COVID-19) pandemic. The largest populations on the continent Nigeria, Ethiopia, Egypt, and the Democratic Republic of Congo are the most populous African countries. In 2023, people living in Nigeria amounted to around 224 million, while the number for the three other countries exceeded 100 million each. Of those, the Democratic Republic of Congo sustained the fourth-highest fertility rate in Africa. Nigeria and Ethiopia also had high rates, with 5.24 and 4.16 births per woman, respectively. Although such a high fertility rate is expected to slow down, it will still impact the population structure, growing younger nations.

In 2022, the urban population in Vietnam stood at approximately 37.4 million people. The six largest urban agglomerations include Hanoi, Hai Phong, Da Nang, Bien Hoa, Ho Chi Minh City, and Can Tho. On the other hand, Ben Tre, Thai Binh, and Bac Giang had the lowest rates of urbanization in the country.

Urbanization in Vietnam

The rapid urbanization in Vietnam results in a disproportionate population density between its urban and rural areas. For instance, in 2022, Ho Chi Minh City recorded a population density of 4,481 inhabitants per square kilometer, nearly 15 times the country's average population density in the same year. The urban population is consistently increasing due to the country’s economic reforms and infrastructure development, as well as higher living standards. For example, the monthly income per capita in urban areas is nearly half as much as that in rural areas. Nevertheless, the poverty rate in Vietnam has been consistently diminishing each year, roughly at 4.2 percent as of 2022.

Urban infrastructure in Vietnam

Vietnam has made significant progress in developing its urban infrastructure, especially in major cities like Hanoi and Ho Chi Minh City. The expansion of highways, seaports, and airports has enhanced domestic and international connectivity, as well as greatly contributed to the country’s logistic industry. For instance, Hanoi and Ho Chi Minh City are developing a metro system which is expected to be put into operation in 2024. The country has also invested in modern healthcare facilities, schools, and commercial centers. However, challenges such as traffic jams, limited public transportation services, and environmental pollution still require significant efforts to meet the growing demands of the Vietnamese urban population.