The Pew Forum on Religion and Public Life reports that although the number of Americans who identify as Atheist or lack a religious affiliation has increased, many of them still believe in God. About 20% of US adults are either Atheist, Agnostic, or lack any religious affiliation. However, of the 46 million adult Americans who are unaffiliated, two-thirds report that they believe in God and one-fifth report that they pray on a daily basis.

Among those 65 and older, 90% are religiously affiliated. Among those 18-29, only 67% have a religious affiliation. Interestingly, the decline has not been uniform among all religions. Protestants have taken the largest hit. Between 1972 and 2010, there was an 11% dip in the number of adult Americans who identified as Protestant. However, those identifying as Catholic remained relatively stable during the same time period, with 26% identifying themselves as Catholic in 1972 compared to 25% in 2010. Moreover, the rise in the number of Americans who identify as religiously unaffiliated could have major implications for future elections. Americans who lack a religious affiliation tend to lean Democrat, with nearly 63% of those registered to vote reporting that they are either Democrat or lean towards the party.