Gallup first began polling Americans on church membership in 1937. In the six decades that followed, between 68% and 76% of Americans said they belonged to a place of worship. Then, at the turn of the century, a persistent decline in religious membership began – and has continued for 20 years.
More than 6,000 Americans were polled in the latest Gallup poll, and 47% now say they are a member of a church, synagogue or mosque. It’s the first time the percentage dipped below 50% since Gallup was founded in 1935.
About 70% of Americans identify as Christian, the Pew Research Center found. About 2% of Americans identify as Jewish and nearly 1% are Muslim. Those represent the largest religious groups in the United States.
The decline in membership coincides with an increase in the number of Americans who do not identify with a particular religion, according to Gallup.
In the past three years, about 21% of Americans say they do not have a religious preference. This is a sharp increase from the 8% mark from 1998 to 2000.
There is also a decline in church membership among US adults who are religious. From 1998 to 2000, about 73% of Americans who have a religious preference went to church, but that number has dropped to 60%, according to Gallup.
“Church attendance is the first thing that goes, then belonging and finally belief – in that order. Belief goes last,” Ryan Burge, a political scientist at Eastern Illinois University and a Baptist minister, told Religion News.
A 2019 Pew Research poll supports Gallup’s new findings. Pew found that 65% of adults in the country described themselves as Christian – down 12 percentage points from a decade prior.
There are also generational differences with religious membership, Gallup found. Just 36% of millennials, the portion of the population born between 1981 and 1996, belong to a church, mosque or synagogue. The percentage grows for each age group – 50% for Generation X, 58% for baby boomers and 66% for traditionalists, who are born before 1946.
Only 6% of millennials engage in religious activities daily, compared to 11.3% of Americans older than the millennial age group, the US Bureau of Labor Statistics found in 2019.
Young adults often participated less in religious activities while growing up than older generations, which could influence their beliefs as they come into adulthood, according to a 2019 poll from the American Enterprise Institute. The poll found 52% of those aged 65 or older attended religious activities at least once a week when growing up, while 29% of those aged 18 to 29 reported the same.
There is a decline in membership at churches, mosques and synagogues in all demographics, but there is a large divide along the lines of political affiliation.
Since 1998, there has been a 20% drop in self-identified political moderates and liberals who are a part of a place of worship, Gallup found. Just 14% of Republicans have dropped membership in the same time frame.
“At that critical moment when people are getting married and having kids and their religious identity is becoming more stable, Republicans mostly do still return to religion – it’s Democrats that aren’t coming back,” religious author Michele Margolis told FiveThirtyEight.
Gallup's poll was based on telephone interviews conducted 2018-20, with a random sample of 6,117 adults, aged 18 and older, living in all 50 US states and the District of Columbia. For results based on the total sample of national adults, the margin of sampling error is plus or minus 2 percentage points at the 95% confidence level.