Alas, I can't justify this by citing any formal study, but the AG (the group Chuck0's roomie encountered) is almost entirely suburban Southern and Western. Some presence in the Northeast, but very little. Almost *no* real urban presence anywhere in the country. (An exception perhaps worth noting: there is one AG church that I know of in Philly proper; I once heard its minister say, during the Republican Convention in 2000, that Philly [by which he meant the urban, downtown area ] was a "third world country" and that "they" and "them" had ruined it. No points for guessing who he meant.)
The South, Southwest, and West (California, mostly) are the strongest AG areas, followed by the Midwest and the Northeast (trailing far behind). It's probably 66%-33% suburban to rural.
Kendall Clark -- Jazz is only what you are. -- Louis Armstrong