Population pyramid

Expansive population pyramid of Angola for 2005 shows a young and rapidly growing population.

Constrictive population pyramid of China for 2005 shows an older population that won't grow so much.

A population pyramid is a graph. It has two back-to-back bars. These bars show the population in groups of ages, with woman in one side and man in the other side.

The pyramids show the age distribution of the place, which can help in understanding and predicting the development of a country.

There are three types of population pyramids:

Stationary pyramid shows a constant population, with equal birth rate and death rate
Expansive pyramid shows a growing population
Constrictive pyramid shows a shrinking population

In this type of graph, a wide base means a very high birth rate and a narrow base means a low birth rate.

Population Pyramid Media

World population pyramid from 1950 to projected in 2100 (UN, World Population Prospects 2017)
Population age pyramid of Nigeria in 2020, similar to all of sub-Saharan Africa
Median age by country. A youth bulge is evident for Africa, and to a lesser extent for West Asia, South Asia, Southeast Asia and Central America.
Map of countries by fertility rate (2025), according to the Population Reference Bureau
Population pyramid of Afghanistan (Expansive)
Population pyramid of Ecuador (Stationary)
Population pyramid of Italy (Constrictive)
Population pyramid of Qatar (Unbalanced)
Population pyramid of Egypt in 2005. Many of those 30 and younger are educated citizens who are experiencing difficulty finding work.
Nearly half of Libya's 2011 population consists of people younger than age 20.

This short article about science can be made longer. You can help Wikipedia by adding to it.