Age structure

Map 1. Dependency ratio, 2020

Regional distribution of dependency ratios and trends over time

Globally, in 2020, for every 100 persons of working age there were 53 persons who were younger or older. This figure, the dependency ratio, varies considerably across regions. In most economies of Western, Middle and Eastern Africa it is higher than 65 per cent, whereas in Western, Eastern and South-Eastern Asia, it is often lower than 45 per cent. Notable exceptions include Japan (69 per cent) and Israel (67 per cent), as well as Yemen (72 per cent), Timor-Leste (70 per cent) and Iraq (70 per cent).

Globally, for every 100 persons of working age there were 39 children and 14 older people. The proportion of children in the population has steadily declined from the peak of 38 per cent in 1966, to 25 per cent in 2020, while the proportion of the older than 64 rose from 5 to 9 per cent over the same period. The net effect has been a decline of the dependency ratio from 76 to 53 per cent. The aging of the world population is projected to continue in the coming decades.

Figure 1. World population by age group

Non-pyramid shape of developed economies’ population pyramid

Figure 2. Population pyramids, 2020

Comparing population pyramids, we find that in developing economies, older age classes are successively smaller than younger classes. In developed economies, this pattern is reversed, so that the proportions of older age groups are larger and younger age groups are smaller than in developing economies.

In both the developing and developed world, women are the majority for older age groups, whereas the majority of children are boys. In 2020, 49.6 per cent of the world population was female.

Less child dependency, more old-age dependency

Over the next 30 years, the total dependency ratio is projected to rise in most regions. Child dependency ratios will decrease, but it is forecast that this will be compensated for by rising old-age dependency ratios. Africa is the exception, featuring both decreasing child and overall dependency ratios (child: from 72 per cent in 2020 to 52 per cent in 2050, overall: from 78 to 61 per cent). In general, child dependency ratios are projected to fall fastest where they are currently highest.

Contrary to child dependency, old-age dependency is forecast to increase most in the groups of economies where it is already comparatively high. This is the case in developed economies, where an increase from 30 per cent in 2020 to 46 per cent is expected by 2050.

Figure 3. Dependency ratio by age structure
Note: The total dependency ratio is the sum of the child and old-age dependency ratios.

Concepts and definitions

In this section, the term “persons of working age” refers to persons aged from 15 to 64 years. The term “children” refers to persons under the age of 15. The term “older persons” refers to persons over the age of 64.

The dependency ratio is defined as the number of children and older persons per hundred persons of working age. It can be expressed as the sum of the child dependency ratio and the old-age dependency ratio.

The child dependency ratio is defined as the number of children per hundred persons of working age. The old-age dependency ratio is defined as the number of older persons per hundred persons of working age.

Except for the world total, data in this chapter exclude data by sex and age for economies with a population of less than 90 000 in 2019.

Summary tables

Table 1. Age structure and dependency ratio
    Table 2. Population by age class, 2020
      Table 3. Female population by age class, 2020