I wonder how Apple accounted for these devices, because if all inclusive, this would also include any active Hackintoshes that have been built and still in use. If that is the case, then not only purely Apple products are being counted.
I know for a fact that while I started back at Apple with my iPhone 3G, then went to a 4s, I started back with a Hackintosh to get my feet wet with OSX before going completely MBA. And judging how active a place like tonymacx86 is, there are definitely more hackintoshes out there than my old box.
BL.