Is there an online source which lists, by religion, the percent of adherents who describe themselves as ‘devout’, ‘orthodox’, ‘not practising’, ‘secular’, ‘just for the holidays’, etc.?
I am mostly interested in figures for North America and Europe.
OKCupid has fields with something like “Protestant and devout,” “Jewish and not serious about it,” “SubGenius and laughing about it.” Maybe I made up some of that.
I think the Pew Forum’s extensive surveys on U.S. religious life could be very close to what you are looking for.
Go here, and click on “Beliefs and Practices.” You can choose any faith.
While there is no “orthodoxy” question, but you can see how many people of each faith believe in God, believe their religion is the only way to get to heaven, etc. Not quite what you were asking, but close.