I pretty sure he's referring to this "hospital circumcision rates declined in the United States: from 64.5% in 1979 to 58.3% in 2010."[1]. So that implies at least 58% of newborns in a hospital are circumcised. Not a statistician or a census bureau employee but I'm pretty sure the US doesn't have >50% practicing Jewish + Muslim folks.

https://en.wikipedia.org/wiki/Prevalence_of_circumcision#Uni...