(CN) — Christianity in the U.S. is quickly declining while Americans with no religious affiliation continue to rise, the Pew Research Center reported Thursday.
After interviewing 168,890 U.S. adults since 2009 — part of 88 phone surveys conducted by random-digit dialing — Pew found that 65% of Americans identify as a Christian, based on 2018 and 2019 phone calls, down 12 percentage points from 2009.
Meanwhile Americans who do not affiliate with a religion, sometimes referred to as “nones,” grew rapidly over the 10-year period: 26% identify now as Atheist, Agnostic or not at all, which is up from 17%.
Catholicism and Protestantism took a hit to their population share over the last decade with 43% of Americans identifying as a Protestant, down from 51% in 2009. Catholics now make up 20% of adults, down from 23%.
Age appears to play a factor in the decline, with about half (49%) of millennials identifying as Christian, compared to three-quarters of baby boomers. The Silent Generation, members of whom were born between 1928 and 1945, make up the largest Christian population with 84%.
Politically speaking, while Christianity has dropped amongst both Republicans and Democrats, it is more noticeable in Democrats. In 2009, 72% of Democrats said they were Christian. Now only 55% identify as such, compared to 79% of Republicans down from 86%.
The study also found that gender continues to play a role in religion, noting that more women identify as Christian than men, but both have become less religious over the decade. In 2009 73% of adult men said they were Christian, compared with 80% of women. Those numbers dropped to 61% and 69%, respectively, in 2019.
Despite the decline in Christianity, the rate of religious attendance has remained the same over the last 10 years with 62% of adults saying they attend a service at least once or twice a month.
Non-Christian religions held steady over the decade with Judaism remaining at 2% of the population and Islam at 1%.