The U.S. is a nation of religious drifters, with about half of adults restlessly switching faith affiliation at least once during their lives, a new survey has found.

And the reasons behind all the swapping depend greatly on whether one grows up kneeling at Roman Catholic Mass, praying in a Protestant pew or occupied with nonreligious pursuits, according to a report issued Monday by the Pew Forum on Religion and Public Life.

While Catholics are more likely to leave the church because they stopped believing its teachings, many Protestants are driven to trade one Protestant denomination or affiliation for another because of changed life circumstances, the survey found.