This is a BBC report on a large study of demographic changes in Europe. The year 200 was a watershed year, "Europe is now in a negative population momentum."
"On average, women in Europe now have a fertility rate of 1.5 births each.
If this continues until 2020, they say it could lead to at least 88m fewer people living in the EU in 2100, assuming constant levels of mortality and no significant effects of migration.
In 2000, the EU population was around 375m, so this would mean a fall of more than 23%."