Per Capita
Etymology
Latin for “by heads,” from “per” (by) plus “capita,” the plural of “caput” (head). It entered English through legal and administrative Latin, where inheritances and taxes were reckoned head by head.
noun phrase · /pur KAP-ih-tuh/
A figure divided by the number of people, giving an amount “per person.”
What it names
It lets you compare places or groups of wildly different sizes fairly, instead of being fooled by raw totals.
Example
China emits far more carbon in total than Sweden, but per capita the ranking can flip once you divide by population.
Related idea
Per capita is a rate, not a level: a country can have rising total output while per-capita output falls, simply because its population grew faster than its economy.
See also