Americans’ membership in houses of worship continued to decline last year, dropping below 50% for the first time in Gallup’s eight-decade trend. In 2020, 47% of Americans said they belonged to a church, synagogue or mosque, down from 50% in 2018 and 70% in 1999.

U.S. church membership was 73% when Gallup first measured it in 1937 and remained near 70% for the next six decades, before beginning a steady decline around the turn of the 21st century…

Gallup asks Americans a battery of questions on their religious attitudes and practices twice each year. The following analysis of declines in church membership relies on three-year aggregates from 1998-2000 (when church membership averaged 69%), 2008-2010 (62%), and 2018-2020 (49%). The aggregates allow for reliable estimates by subgroup, with each three-year period consisting of data from more than 6,000 U.S. adults.