The decline in birth rates in European countries below the population replacement level has been a gradual process over the years. The earliest decline was noted in Serbia in 1962, followed by other countries such as Croatia, Belgium, Finland, and Germany in the late 1960s.

Post-Soviet countries experienced this demographic shift later, with Belarus dropping below replacement levels in 1984, followed by Ukraine, the Baltic countries, and others in the late 1980s. Surprisingly, Turkey remained above replacement levels until 2016. Meanwhile, Iceland stands out as the last European country to see a decrease in birth rates, which occurred in 2010.