The nation's Christians are experiencing a steep slide in numbers, according to a new Pew Research Center poll. The survey of 35,000 adults finds the number of those who identify as Christian slid from 78.4% in 2007 to 70.6% in 2014, the New York Times reports. Almost every major Christian denomination saw a decline, and no age group, race, or region was immune. The trend "is big, it's broad, and it's everywhere," report editor Alan Cooperman tells USA Today. "The decline is taking place in every region of the country, including the Bible Belt," he adds, per the Times. While some of the slide is attributed to non-Christian millennials supplanting the elderly, many once-Christians have shifted to the unaffiliated category of atheists, agnostics, and those of "no particular religion," which has grown from 16% of adults to 23%.
That means the 56 million "nones" are now the second-largest faith group behind evangelicals, who make up about a quarter of the religious market. Catholics make up about 21% of the population, though Roman Catholics and mainline Protestants saw the greatest declines, each falling by more than 3%. Evangelical Protestants actually grew in number but fell by 1% as a share of the overall population. About 19% of adults are now ex-Christians and 13% are former Catholics, the report finds. "Overall, there are more than four former Christians for every convert to Christianity," Cooperman says. Affiliations with non-Christian faiths, including Judaism, Islam, and Hinduism, rose slightly from about 5% in 2007 to 6% in 2014. Experts say the survey will have political consequences and may be greatest felt by conservatives and Republicans, who typically rely on white Christian voters, the Times reports. (Read more Christians stories.)