I don't think they release a concrete revenue figure to the public.
but they earn a lot.
Your 2nd question is really vague I mean there's a lot of american acts and their concert revenues varies some of them can just gross a million and some of them can gross 200 millions or higher. These are the highest grossing tours found on Wikipedia
http://en.wikipedia.org/wiki/List_of..._concert_tours
Lastly you can't really compare them because most of (if not) all of those highest grossing tours are a World tour with a lot of dates while Ayu only tour in Japan and some part of Asia.