Looking for statistics on Americans who go abroad.....

Does anyone know where I could find statistics on:

  1. Americans who travel/study abroad
  2. How long they stay
  3. where they go
  4. how much this has increased over the decades?
    I know that iie.org has a lot of good statistics, but I’m looking for some other sites as well.

Any statistics concerning Americans going abroad, really, would be helpful.