The U.S. religious marketplace is extremely volatile, with almost half of American adults leaving the faith of their upbringing to either switch allegiances or abandon religious affiliation altogether, a new survey finds.
The study released Monday by the Pew Forum on Religion and Public Life is unusual for its sheer scope, based on interviews with more than 35,000 adults.
The U.S. Religious Landscape Survey estimates the United States is 78 percent Christian and about to lose its status as a majority Protestant nation, at 51 percent and slipping.
More than one-quarter of American adults have left the faith of their childhood for another religion or no religion at all, the survey found. Factoring in moves from one stream or denomination of Protestantism to another, the number rises to 44 percent.
The religious demographic benefiting the most from this religious churn is those who claim no religious affiliation. People moving into that category outnumber those moving out of it by a three-to-one margin.
The majority of the unaffiliated — 12 percent of the overall population — describe their religion as "nothing in particular," and about half of those say faith is at least somewhat important to them.
Findings by belief
• Catholic: Despite losing more followers than other beliefs, 24 percent of the population is Catholic. The number is steady due to its popularity among immigrants. Ten percent of the U.S. population is an ex-Catholic.
• Hindu: 84 percent of people raised Hindu remain Hindu.
• Buddhists: The poll found 0.7 percent of respondents identified themselves as Buddhists. More than half were white, and more than half converted from another faith. It was unclear whether these were people with a core belief, or if they associated themselves with it because they practice yoga and meditation.
• Mormons and Muslims: These groups have the largest families; More than one in five Mormon adults and 15 percent of Muslim adults in the United States have three or more children at home.
• Atheist/agnostic: Four percent categorize themselves as such.