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

The relative sizes of secular and religious populations belong to the mostimportant 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 lowfertility are also likely to change when there is a growth of religious groups whereconversion/secularisation rates are low and childbearing levels are high. Weproject the membership size of the various religious groupings until 2051 forAustria, a country where the religion question is included in the census, allowingdetailed and accurate projections to be made. We consider relative fertility rates,religion-specific emigration and immigration, conversion rates andintergenerational transmission of religious affiliation. Our estimates suggest thatthe 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, willrepresent 14% to 18% of the Austrian population by 2051, and could represent upto 32% of those below 15 years of age. The Protestants’ population share will bestable at around 4%, while up to 34% of the population will be without religion.