This article collects statistics about atheists in America and worldwide.
In America:
Research has shown that most atheists tend to lean to the left in terms of their politics. About 69% of non believers are Democrats while 56% consider themselves to be politically liberal. In keeping with this finding 92% of atheists support same sex marriage and 87% approve of legal abortion. Atheists are also more likely to be young (the median age being 34), male (68%), white (78%), and educated (with 43% having a college degree).
…According to the Pew Research Center in terms of the U.S. adult population the average age of Christians was 49 in 2014 which is up from 46 in 2007. This comes as a contrast to atheists whose average age fell from 36 in 2007 to 34 just seven years later. American Jews remained steady over this time period with a median age of 50.

