Researchers say the expected decline can be predicted a dwindling number of baptisms in Germany, the number of Germans who have departed from formal religious enrollment, and a decrease in Germany’s overall population, which is expected by 2060 to be reduced by 21%.

In total, the number of Germans who pay the country’s Church tax is expected to decrease by 49%. German law collects an income tax on the country’s Church members, which it dis-tributes to Church organizations, among them the Catholic Church and the Evangelical Church of Germany, a federation of Protestant groups, mostly Lutheran, which constitutes the largest Protestant group in Germany.

Taxpayers have the option of opting out of tax payment by notifying state authorities that they have left the religious group in which they are enrolled. In 2017, the Church tax generated $13.5 billion for religious groups in the country. The predicted decline in membership would lead to major budget shortfalls for the Catholic Church in Germany.