A stereotype I’ve had of the past, received from various media, is that in North America, in more conservative times, i.e., up until the liberalization of society in the late 1960s and 1970s, almost everyone went to church on Sunday (unless you were Jewish, in which case you probably went to synagogue on Saturday, or belonged to one of the then-very-much in the minority ethnic groups that were not traditionally Judaeo-Christian). Also, that back then (and much more recently), almost everyone believed in God, or if you didn’t, you generally kept quiet about it.
However, a statistic that I have found in some sources (e.g. here) claims that the highest rate of churchgoing in the USA (as in, the percentage of people who attended church at least once a week) was 49%, in 1955 and again in 1958. If this statistic is correct, that means that, even at churchgoing’s 20th-century peak, a very slight majority was not attending church!
This begs the question of what lies behind the statistic. Is there any way in which those who in 1955 went to church and those who didn’t could be distinguished?
For example, were young people who had not yet gotten married, bought a house, and started a family, and so did not feel they needed to present an image of respectability in a specific community among those that tended not to go to church, becoming churchgoers when they settled down?
Or would the statistic for those who did not go to church have included a lot of people from big cities where it was easier to remain anonymous?
It is interesting that, for example, Walt Disney is claimed not to have attended church as an adult, despite the fact that he was a public figure who built a strong impression of family respectability around his business. Would he have needed to justify himself in some way?