Maybe you could just email Kurt Stache, President of the AAdvantage program, directly. I'm sure he'd be happy to share that sort of information. But my educated guess is 90% or so are in the U.S. And the better question to ask is "what percent of active members" live where. AAdv loves to throw around 50 million members as their total membership, but in truth the number of those actually doing something with the program over the last year to two years is more like 12-13 million. The remainder are inactive, dead, terminated accounts, dupes, etc.

FWIW, both my wife and I are AAdv members, and live in the U.S., so that's a few more here.