New times, old beliefs: Projecting the future size of religions in Austria

The relative sizes of secular and religious populations belong to the most important social characteristics of each country. In the wake of religious change, family behaviour, including marriage and childbearing, is likely to be altered. European demographic trends, including those of late childbearing and low fertility are also likely to change when there is a growth of religious groups where conversion/secularisation rates are low and childbearing levels are high. We project the membership size of the various religious groupings until 2051 for Austria, a country where the religion question is included in the census, allowing detailed and accurate projections to be made. We consider relative fertility rates, religion-specific emigration and immigration, conversion rates and intergenerational transmission of religious affiliation. Our estimates suggest that the Catholic proportion will decrease from 75% in 2001 to less than 50% in 2051. The Muslim population, which grew from 1% in 1981 to 4% in 2001, will represent 14% to 18% of the Austrian population by 2051, and could represent up to 32% of those below 15 years of age. The Protestants’ population share will be stable at around 4%, while up to 34% of the population will be without religion.