A newly released national survey of roughly 2,000 respondents age 18-24 finds that "One in four young adults choose 'unaffiliated' when asked about their religion," the Washington Post reports. The article also notes that "...most within this unaffiliated group — 55 percent — identified with a religious group when they were younger."
The larger report, including methodology, is available here. Though the focus of the survey was religion (having been sponsored by two religion research institutes), it also delves into areas such as relations with parents, social media use, politics/voting, and economic and social issues.
It is interesting to speculate on why many young adults have abandoned their earlier religious affiliations. Christianity is the numerically dominant religious identification in America, so attitudes toward it presumably would say a lot about attitudes toward organized religion in the U.S. more generally. According to the larger report of the recent survey, many young people see negative qualities (as well as positive ones) in contemporary American Christianity:
Almost two-thirds (64%) of Millenials say that "anti-gay" describes present-day Christianity somewhat or very well. Over 6-in-10 (62%) also believe that present-day Christianity is "judgmental," while 58% agree that "hypocritical (saying one thing, doing another)" describes present-day Christianity well (p. 31).