Pew Research Report on religious declines in general in U.S.
"In U.S., Decline of Christianity Continues at Rapid Pace," Pew Research Center, October 17, 2019, accessed October 21, 2021
65% of American adults describe themselves as Christians when asked about their religion, down 12 percentage points over the past decade. Meanwhile, the religiously unaffiliated share of the population, consisting of people who describe their religious identity as atheist, agnostic or “nothing in particular,” now stands at 26%, up from 17% in 2009.