Americans have less faith in organized religion than they did nearly a decade ago, a new study shows.

A staggering 21 percent of those surveyed said they don’t practice a “formal religion” — up from the 15 percent who said that in 2008, according to Gallup.

“Religion is losing influence in society,” according to Gallup, which did not offer a reason for the decline. “This may be a short-term phenomenon or an indication of a more lasting pattern.”

Overall, 74 percent of Americans identified as Christian and 2.1 percent said they were Jewish; 1.8 percent said they were Mormon and .8 identified as Muslim, according to the pollsters.

Everyone else either claimed to be “none/ atheist / agnostic” or gave no response at all, researchers said.

The number of true believers has dropped dramatically since the 1940s and 1950s, when less than 3 percent said they practiced no formal religion.

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