Religious 'Nones' are now the largest single group in the U.S.

Religiously unaffiliated people now make up 28% of U.S. adults, according to a new study from Pew Research. That's a larger cohort than Catholics or evangelical Protestants. (Natacha Pisarenko/AP)

When Americans are asked to check a box indicating their religious affiliation, 28% now check 'none.'

A new study from Pew Research finds that the religiously unaffiliated – a group comprised of atheists, agnostic and those who say their religion is "nothing in particular" – is now the largest cohort in the U.S. They're more prevalent among American adults than Catholics (23%) or evangelical Protestants (24%).