By John McDevitt

PHILADELPHIA (CBS) — A new study indicates that the number of Americans who claim no religious affiliation is on the rise.

The survey was done by the Pew Research Center, where Greg Smith helped analyze the data.

“We asked  them, ‘When it comes to your current religion, what if anything are you?  Protestant, Catholic, Jewish, Muslim?’   And this large group of people, about one in five American adults, say that they don’t associate with any particular religion,” he tells KYW Newsradio.

Smith says many of the religiously unaffiliated do think of themselves as either religious or spiritual, including about one-third who say they’re spiritual but not religious.

In the 1990s, Pew found fewer than one in ten American adults were religiously unaffiliated.   Since that time it’s been on the rise to where it stands today, at 20 percent of adults saying they don’t belong to a specific religion.