Fewer than half of U.S. adults now claim membership in a church, mosque or synagogue, according to a Gallup report published March 29.
This is the first time in polling history when a majority has not done so, following a decades-long membership decline.
Gallup began polling on this question in 1937, when 73% said they were members of a house of faith. That number ticked up to 76% over the next decade before stabilizing at 73% until the mid-70s when membership dropped slightly to 71%.
From 1977-99, membership was relatively consistent, moving between 71% and 68% before seeing a steady downward trend over the next two decades. In 2020, 47% of U.S. adults claimed membership in a church, mosque or synagogue.
While all age groups have seen a decline, membership is significantly lower among younger adults.
From 2018-20, an average of 36% of Millennials (born 1981-96) said they were part of a house of faith, compared to 50% of Generation X (born 1965-80), 58% of Baby Boomers (born 1946-64) and 66% of Traditionalists (born before 1946), during the same period.
Millennials’ average membership dropped 15 points between 2008-10 and 2018-20, compared to seven points for Generation X, five points for Baby Boomers and seven points for Traditionalists.
A key part of this membership trend is that the number of adults who claim no faith affiliation has been increasing across all age groups.
“Since the turn of the century, there has been a near doubling in the percentage of Traditionalists (from 4% to 7%), Baby Boomers (from 7% to 13%) and Gen Xers (11% to 20%) with no religious affiliation,” the report said.
Since 2008-10, Millennials claiming no religious affiliation have increased nine points to 31%.
These increases account for more than half of the membership decline, with the other portion resulting from a drop in the number of respondents who claim a faith tradition but are not members of a church, mosque or synagogue.
Since 2008-10, membership among Traditionalists who affiliate with a religious tradition has dropped six points to 72%, compared to a four-point decline for Baby Boomers (down to 65%), eight points for Generation X (to 60%) and 13 points for Millennials (to 50%).
“The U.S. remains a religious nation, with more than seven in 10 affiliating with some type of organized religion. However, far fewer, now less than half, have a formal membership with a specific house of worship,” the report said.
“While it is possible that part of the decline seen in 2020 was temporary and related to the coronavirus pandemic, continued decline in future decades seems inevitable, given the much lower levels of religiosity and church membership among younger versus older generations of adults.”
The margin of error is plus-or-minus 2%. The full report is available here.