Whereas 39% of all US adults lived without a partner or spouse in 2007, that number has risen to 42% in 2017, according to data from the US Census Bureau.

“People are more conscious of the potential costs” of living together, said Stephanie Coontz, director of research and public education for the Council on Contemporary Families, a nonpartisan group of experts and researchers.

“A good part of it, of course, is the delay in marriage,” said Coontz, who was not involved in the Pew analysis.