To create a larger category of the nonreligious, Ive combined atheists, agnostics and people who said both that they didnt belong to a religion and that religion wasnt important to them. This group made up 15.8 percent of the United States population in 2014, up from 10.3 percent only seven years earlier, according to Pew.
And the share seems likely to continue growing because young people are much more likely to be secular than middle-aged and older adults.
A remarkable 25 percent of Americans born after 1980, the group often known as millennials, are not religious, compared with 11 percent of baby boomers and 7 percent of the generation born between 1928 and 1945.
Its not clear that millennials will become much more religious as they age, either. Despite the cliché about people getting more religious as they get older, it hasnt been happening recently. No generation has become more religious since 2007, according to the Pew data. Baby boomers and the so-called Generation X have become slightly less religious over that time, and millennials have become substantially less.
http://www.nytimes.com/2015/05/13/upshot/the-rise-of-young-americans-who-dont-believe-in-god.html?abt=0002&abg=0&_r=0