Since 1999, the number of people saying they belong to a specific church, synagogue or mosque has dropped 20%, according to a new Gallup poll.
The polls also found the number of people who identify as such has steadily decline every year, with 2020 data showing less than half of Americans now belong to a house of worship.
When Gallup began studying religious identities in 1937, about 73% of Americans claimed membership in houses of worship –until 1999 when a steady decline began across the nation.
The poll found that in 2020 about 47% of U.S. adults belonged to a church, synagogue or mosque, down more than 20 points from the turn of the century.
The polls also found that thousands of U.S. churches are closing each year and attributed the closures to a variety of factors including shrinking religious practices and pandemic responses.
Gallup said the decline in church membership is a direct relation to the increasing number of Americans who don't express any religious preference. The number of Americans who don't identify with any religion has nearly tripled from 8% in the 2000s to 21% in recent years.
The declines correlate with social factors such as political affiliation, generation and religious groups. Declines in membership are smaller among political conservatives than Democrats and steeper among Catholics than other subgroups like protestants, the poll found.