We find that economic growth responds positively to the extent of religious
beliefs, notably those in hell and heaven, but negatively to church attendance. That is, growth depends on the extent of believing relative to belonging.
Full paper by Barro and McCleary. (Five years old.) Unfortunately, the data under consideration here only cover 1981-1999. I would like to see this subject attacked from a historical basis, e.g. Rome, Dark Ages, etc, etc, etc. File that one under 'neat regressions that will only be run after we develop a time machine to collect the appropriate data'. It's a big folder.