Forty percent of all births in the U.S. now occur outside of wedlock, up from 10 percent in 1970, according to an annual report released on Wednesday by the United Nations Population Fund (UNFPA), the largest international provider of sexual and reproductive health services. That number is even higher in the European Union, where 60 percent of births occur outside of marriage.

The EU likely sees more births out of wedlock because many member countries have welfare systems that support gender-balanced child care, said Michael Hermann, UNFPA’s senior adviser on economics and demography, in an interview. Public health care systems, paid paternal leave, early education programs and tax incentives give unwed parents support beyond what a partner can provide.