The median age of a population is the point at which half
the population is older than that age and half is younger. Median ages vary
significantly across the globe, and are influenced by a number of factors,
such as birth rates, social and economic development and average life expectancies
within individual countries.
These differences can be seen in highly developed countries such as Japan,
where the median age is 46.9 years, and Germany at a median age of 46.8 years.
In contrast, the majority of countries with median ages under 20 years are in Africa.
This is reflective of the fact that poverty, disease and conflict situations
cause lower life expectancy figures in many African countries.