Religious affiliation in the United States is both diverse and extremely fluid, according to a new survey from the Pew Forum on Religion & Public Life. Based on interviews with more than thirty-five thousand Americans, the U.S. Religious Landscape Survey finds that 28 percent of American adults have left the faith in which they were raised in favor of another religion or no religion at all, with Catholicism experiencing the greatest net loss as a result of affiliation changes. Indeed, while 31 percent of Americans were raised in the Catholic faith, today only 24 percent describe themselves as Catholic. Meanwhile, among Americans between the ages of eighteen and twenty-nine, 25 percent say they are not currently affiliated with any particular religion.