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NumberReels

Chart type · Trend

Pyramid

Back-to-back bars by cohort, read as a shape.

How to read it

Bars run back to back from a shared centre, oldest band on top. Compare the shapes of the two profiles: a wide base is a young, growing population, a top-heavy one is ageing. The dashed line on each side marks its median age, and the chip under it names the shape.

Best for

Population pyramids: one population split in two, two countries compared by share, or one country aged from then to now.

When not to use it

The cohorts aren't an ordered ladder (ages, income bands), so there is no shape to read.

The common mistake

Comparing two populations of different size in absolute counts, where every band favours the larger one. Compare each side's share of its own total instead.

Example data

Two countries, two completely different futures

Share of population by age band, 1975 → 2025

Japan

Year

Nigeria

The sample dataset this format ships with, drawn the way the site draws every clip's numbers — hover, sort or step through it. Figures as given by its source line: UN WPP 2024 (approx. — verify before publishing).

1 pyramid reel

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