Population is the total number of people resident in a country on 1 January each year. It looks like a simple count, but it underpins a great deal.
Why it matters
It is the denominator for per-capita measures — GDP per capita, money supply per person, debt per head.
An ageing, slow-growing population raises pension and health spending while shrinking the working-age base that funds it.
Most EU population change now comes from migration rather than natural increase (births minus deaths), which has turned negative in many member states.
Source: Eurostat demographics, population on 1 January, annual.