Religious affiliation – 20% now label themselves as “none.”

And it's one in three for adults under 30.

Study is by the Pew Research Center and this is a good summary article from yeserday's Chicago Tribune.

The number of adults who consider themselves atheist, agnostic or "nothing in particular" has increased from about 15 percent to nearly 20 percent in the last five years, the highest percentage ever for that group in Pew polling.

Fifty-eight percent of Americans still say religion is very important in
their lives, far exceeding the value given to religion by people in
Britain, France, Germany or Spain, Pew said.

The
survey by the Pew Research Center's Forum on Religion & Public Life
also found that many of the country's 46 million adults who don't claim a
religion remain religious and spiritual in some way even though most
are not seeking a denomination.

Seventy-three
percent of U.S. adults are Christian, but the number of Protestants
dropped to 48 percent in 2012 from 50 percent in 2011 and 53 percent in
2007, the poll showed. Pew said it was the first time its surveys had
found Protestants to no longer make up at least half of the overall
population.

And it's very good news for the Democratic Party –

Recently the religiously unaffiliated have increasingly voted
Democratic, Pew said, with exit polls conducted by a consortium of news
organizations showing a rise from 61 percent in the 2000 presidential
election to 75 percent in 2008.