Many of the vast differences we see in societies across the globe can be related to the composition of their respective populations. This is true on the local, state, and national levels. So when exploring variations among countries, a good place to start is with their age structure diagrams (population pyramids) – graphs that display the age and sex distribution of the country’s population.
To help make population projections for different countries, demographers look at the profile of the countries’ residents. What are the ages of the people? How many are men? How many are women? Taking this information, they construct population pyramids that depict the configuration of a country’s population as impacted by 70 to 80 years of economic, political, and natural events.