Fewer than half of U.S. adults belong to a religious congregation, a new Gallup study shows. This is down from 70% in 1999. That figure fluctuated only a few percentage points over a period of 6 decades beginning in 1937 (the first time this question was surveyed) when 73% of U.S. adults said they belonged to a church, synagogue, or mosque.
Another Pew study (Feb 2019) showed 69% of US adults use Facebook (74% visit at least once per day), 73% use YouTube. 10 facts about Americans and Facebook | Pew Research Center