@agracier If anything of what you say was factual, then most males in US would be cut since 19th century. However until 70s it was a case for religious reasons only. Then in 70s AAP released its advisory, based on research, and circumcision bloom followed.
The heyday of circumcision in the US was the 1950s. And it was certainly not for religious reasons. Only two religions require circumcision for males as a necessity for inclusion and that is the Jewish religion and Islam. Neither of which groups were numerous in the US.
The US became a nation of circumcised males in spite of a religious prohibition on circumcision. Christianity formally proscribed ritual (not medical) circumcision as it was seen as a practice too entwined with their religious enemies. The formal prohibition is quite old, from 1442 as codified in a Papal Bull:
'A Papal bull, specifically the "Bull of Union with the Copts" issued by Pope Eugene IV in 1442, addressed the practice of circumcision for Christians, stating that those who continued to practice it after the promulgation of the Gospel were essentially strangers to the faith.'
As for a bloom in the US after 1970. Here a CDC graph showing a decline:
https://www.cdc.gov/nchs/data/hestat/circumcision_2013/circumcision_2013.htm
Here is a search when looking from 1950:
'In 1950, the estimated infant circumcision rate in the United States was around 72%. This represents a significant increase from previous decades, with rates rising from 30% in 1900 and 55% in 1925, according to Wikipedia and the National Institutes of Health (NIH). By the end of the 1950s, it's estimated that around 90% of non-Jewish newborn boys were circumcised in hospitals. This rise was partly due to the medicalization of circumcision and the perceived benefits of hygiene and sanitation. '
Compare the 1950 percentages here to the CDC numbers for 1979 and you'll see there is already a significant decrease in the percentages.
It's really best to have a basic knowledge of the historic percentages involved.