Re: Aikido Popularity in U.S.
The last time I made a list, there were over 70 organizations in the US giving dan ranks in Aikido and, as George said about the ASU, the USAF dojos usually don't require their students to become members until their fifth kyu test.
You could use Aikiweb's list of dojos and estimate, although student body size differs vastly from dojo to dojo. There are also, I think, a good number of dojos not on that list.
I suspect we're in the 100,000 range or so.
I wonder if Adidas did any marketing research before bringing out their line of Aikido gear?