NEW YORK (AP) -- For the first time in its history, the United States does not have a Protestant majority, according to a new study.

The Pew Forum on Religion & Public Life says the percentage of Protestant adults in the U.S. has fallen to 48 percent, while the number of Americans with no religious affiliation has increased from 15 to 20 percent in the last five years.

More than 13 million U.S adults describe themselves as atheists or agnostics and 33 million describe thmselves as having no particular religious affiliation, according to the Pew "'Nones' on the Rise" study, and about one third of adults under 30 say they have no religious affiliation.

The trend has political implications. Americans who describe themselves as having no religion vote overwhelmingly for Democrats and support abortion rights and gay marriage at a much higher-rate than the U.S. public at large.

But the unaffiliated include people who still say they believe in God, pray daily or consider themselves "spiritual" but not "religious."

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