1967 and 1968 were the largest, although fertility remained relatively high until 1990. 8.55% of the Romanian population was born in the period from 1976 to 1980, compared with 6.82% of Americans and 6.33% of Britons. Age structure by ethnicity Population by ethnicity based on age groups, according to the 2011 census: Immigration Foreign-born population (according to Eurostat): Religion Romanian Orthodox — 86.7% Roman Catholic — 4.7% Protestant Churches (Calvin, Lutheran, Unitarian, Pentecostal, Baptist, Adventist) — 5.3% Greek Catholic - Uniate — 0.9% Islam — 0.3% Atheist — ≈0.04% (9,271 people) No religion — 0.1% Other religions — 2.0% Refused to declare — 0.1% Religious affiliation tends to follow ethnic lines, with most ethnic Romanians identifying with the Romanian Orthodox Church. The Greek Catholic or Uniate church, reunified with the Orthodox Church by fiat in 1948, was restored after the 1989 revolution. The 2002 census indicates that 0.9% of the population is Greek Catholic, as opposed to about 10% prior to 1948. Roman Catholics, largely ethnic Hungarians and Germans, constitute 4.7% of the population; Calvinists, Baptists (see Baptist Union of Romania and Convention of the Hungarian Baptist Churches of Romania), Pentecostals, and Lutherans make up another 5%. There are smaller numbers of Unitarians, Muslims, and other religions. See also Ageing of Europe Population exchange between Bulgaria and Romania Immigration to Romania Notes References External links United Nations Statistics - Romania Romanian National Statistic Institute (site is in Romanian language, PDF files are in Romanian and English) Population density map