year,weekly_attendance_pct,church_membership_pct,no_religious_affiliation_pct,religion_very_important_pct,source_notes
1937,,73,,,Gallup first measurement of membership
1939,41,,,,Gallup first measurement of attendance
1943,,76,,,Gallup historical high membership
1947,,76,,,"Gallup tied historical high"
1950,39,,,,Gallup
1952,,,,75,Gallup historical high importance
1955,49,~73,2-3,,Gallup peak attendance era
1958,49,,,,Gallup
1960,49,~70,~3,,Gallup; approximate from trend
1965,,,,70,Gallup religion importance
1970,42,~68,~5,,Gallup; beginning of decline
1975,40,~68,~6,,Gallup
1978,,,,52,Gallup historical low importance
1980,40,~68,~7,,Gallup
1985,39,~68,~8,,Gallup
1988,,65,,,Gallup low membership
1990,36,65,~10,,Gallup; nones cross 10% threshold
1993,,,,,Gallup Religion Index lowest point
1995,35,,,,Gallup
1996,<40,,,,Gallup dip year
1998,,69,8,,Gallup 1998-2000 average
2000,44,69,9,,Gallup; 2000-2003 avg attendance 42%
2004,44,,,,Gallup
2005,~40,,,,Gallup
2008,<40,62,13,,Gallup dip year; 2008-2010 avg membership 62%
2010,~39,61,~15,,Gallup
2011,,,,,"Gallup 2011-2013 attendance avg 38%"
2013,~39,,,53,Gallup
2015,~37,54,,,"Gallup; lowest membership to that point"
2018,~36,,~18,50,Gallup; Pew 76% report affiliation
2020,~33,47,21,,Gallup; 2018-2020 avg membership 49%
2021,,,,,"Gallup 2021-2023 avg attendance 30%; nones 21%"
2023,~30,,21,,Gallup 2021-2023 aggregate
2025,~29,,~23,,Gallup projected/latest; attendance continued decline