Twenty-eight percent of American adults have left the faith in which they were raised, switching to another religion or no religion at all, according to a national survey of religious affiliation.
In addition, adults who claim no ties to any religious institution have grown into the fourth-largest category of religious identification, a trend led by California and other states in the West, according to a report by the Pew Forum on Religion and Public Life.
Researchers said the large number of immigrants who have come to California from Central America and Asia have had an effect on the question of religious affiliation in the state as well as the makeup of particular denominations, especially Catholics. While 10 percent of U.S. adults have left the Catholic Church, an influx of Catholic immigrants has kept the church's population stable.
Partly because the numbers of the unaffiliated have grown, Protestants, who have historically been the majority in the United States, are on the verge of losing that status. Only 51 percent of American adults describe themselves as Protestant.
I've talked with a few people who got disgusted with religion in general what with 9/11 and the religious right, but I don't know if that's an important part of the trend.