Population aging refers to the increasing proportion of older adults (typically defined as those aged 65 and above) in a population. It is also known as the ageing population or the graying of the population.

As of 2023, Japan has the highest life expectancy in the world, with an average life expectancy of 84.6 years for women and 81.1 years for men.

The increase in life expectancy in recent decades is attributed to a combination of factors, including improved healthcare, better nutrition, increased physical activity, and improved living conditions.

Age structure, population pyramid, and age distribution are all terms used to describe the distribution of a population by age. They provide a graphical representation of the proportion of individuals in different age groups within a population.

Japan has the oldest population in the world, with a median age of 48.4 years in 2023. This is due to a combination of factors, including low fertility rates and increasing life expectancy.

Population aging can lead to a number of challenges, including increased healthcare costs, a shortage of skilled workers, and a strain on social security systems. These challenges can have a significant impact on the economy and society as a whole.

Japan has the highest proportion of older adults (aged 65 and above) in its population, with 29.1% of its population being 65 or older in 2023.

Aging, senescence, and maturation are all terms used to describe the process of becoming old. Aging refers to the physical, mental, and social changes that occur over time, while senescence specifically refers to the decline in physiological functions associated with aging.

As of 2023, the average life expectancy in the United States is 78.8 years, with women having a slightly higher life expectancy (80.5 years) than men (77.1 years).

The Central African Republic has the lowest life expectancy in the world, with an average life expectancy of 49.6 years in 2023. This is due to a combination of factors, including poverty, poor healthcare, and political instability.

Life expectancy is the term used to describe the number of years that a person is expected to live. It is typically calculated based on mortality rates and other demographic factors.

The decline in fertility rates in many countries is attributed to a combination of factors, including increased access to contraception, later age at marriage, changing social norms, and economic factors.

Niger has the highest fertility rate in the world, with an average of 7.0 children per woman in 2023. This is due to a combination of factors, including cultural norms, lack of access to contraception, and high rates of poverty.

Working-age population refers to the proportion of a population that is of working age, typically defined as 15-64 years old. It is an important indicator of the size of the labor force and the potential for economic growth.

Dependency ratio, age dependency ratio, and old-age dependency ratio are all terms used to describe the ratio of the number of people of working age to the number of people who are not of working age. It is an important indicator of the potential burden on the working-age population to support the non-working-age population.