Bulgaria's population has shrunk to 7.4 million people, a drop of seven percent in the last decade and the latest sign of declining population across the one-time communist countries of central and eastern Europe.

The Bulgarian government said Thursday that a third of the country's people live in its three biggest cities, the capital Sofia, along with Varna and Plovdiv.

The census showed Bulgaria has a growing number of older people, with more than 18 percent of its population over 65. The World Bank says Bulgaria has the European Union's oldest population, which officials say puts strains on the country's pension and health care systems.

Meanwhile, the portion of Bulgaria's youngest citizens — those under 15 — has fallen to just over 13 percent.

Last week, Russia approved its first abortion regulations since the fall of the Soviet Union two decades ago. In part, the new regulations are an attempt to halt the decline in Russia's population.