Between 2007 and 2014, the number of Americans who didn't identify with any religion jumped from 36.6 million to 55.8 million.
A Pew survey of 1,300 non-religious people provides deeper insight into what is driving this phenomenon, as told by the non-religious themselves.
When asked why they don't identify with any religion, a majority of respondents — 60 percent — said that they question a lot of religious teachings (respondents were allowed to give multiple answers).
Forty-nine percent said they opposed the positions taken by churches on social and political issues.
Forty-one percent said that don't like religious organizations, while 36 percent said religion is irrelevant to them and 34 percent said they dislike religious leaders.
Only 37 percent gave not believing in God as their reason for rejecting religion, highlighting the fact that many non-believers do not necessarily identify as atheists or even as agnostics. "Those who identify as atheist, agnostic or 'nothing in particular' tend to give different reasons for their lack of affiliation, showing that nones' are far from a monolithic group," wrote Pew research associate Becka Alper. "For example, about nine-in-ten self-described atheists (89%) say their lack of belief in God is a very important reason for their religious identity, compared with 37% of agnostics and 21% of those in the 'nothing in particular' category. Atheists also are more likely than other 'none' to say religion is simply 'irrelevant' to them (63% of atheists vs. 40% of agnostics and 26% of adults with no particular religion)."
About two-thirds of those who identify as agnostic or atheist are white men with higher levels of education. Overall, though, atheists and agonistics make up a minority of the non-religious, with a majority saying they're just nothing in particular with regard to religion.