A population pyramid displays the population distribution across all ages, for both sexes. The chart can help identify and project future trends.
The population pyramid is a specific type of histogram, or rather a pair of histograms, positioned back to back. Each histogram shows the frequency distribution of the population across age brackets (one for males and the other for females). Population pyramids are useful in fields such as economics, sociology, and ecology as they help indicate population patterns and future trends. A population pyramid with a wide base and narrow tip for example indicates a young, dependent, population, with high fertility rates and low death rates. Future trends are also speculated using these charts.