U.S. church membership was 70% or higher from 1937 through 1976, falling modestly to an average of 68% in the 1970s through the 1990s. The past 20 years have seen an acceleration in the drop-off, with a 20-percentage-point decline since 1999 and more than half of that change occurring since the start of the current decade…

The decline in church membership mostly reflects the fact that fewer Americans than in the past now have any religious affiliation. However, even those who do identify with a particular religion are less likely to belong to a church or other place of worship than in the past.