People in the U.S. are leaving and switching faith traditions in large numbers. The idea of “religious churning” is very common in America, according to a new survey from the Public Religion Research Institute (PRRI).

It finds that around one-quarter (26%) of Americans now identify as religiously unaffiliated, a number that has risen over the last decade and is now the largest single religious group in the U.S. That’s similar to what other surveys and polls have also found, including Pew Research.

PRRI found that the number of those who describe themselves as “nothing in particular” has held steady since 2013, but those who identify as atheists have doubled (from 2% to 4%) and those who say they’re agnostic has more than doubled (from 2% to 5%).

As for why people leave their religions, PRRI found that about two-thirds (67%) of people who leave a faith tradition say they did so because they simply stopped believing in that religion’s teachings.

And nearly half (47%) of respondents who left cited negative teaching about the treatment of LGBTQ people.

Those numbers were especially high with one group in particular.

“Religion’s negative teaching about LGBTQ people are driving younger Americans to leave church,” Deckman says. “We found that about 60% of Americans who are under the age of 30 who have left religion say they left because of their religious traditions teaching, which is a much higher rate than for older Americans.”