statistics on riding sports

Question
Hi,
Do you know or could you find information or websites for me about the percent of people either in the U.S. nation, Europe, and/or the world that compete (but just riding is ok too) in the following (or most of the following) riding sports: flat racing, steeple chasing, harness racing, show jumping, eventing, dressage, endurance riding, showing, and western riding. I am especially interested in finding the percent of people that ride and/or compete in dressage. I know your areas of knowledge aren't in statistics about riding, but I simply need help finding this information. Thank you so much!

Answer
Hi Ruth.
  I don't believe it's possible to answer this question. You could try to check with various registries, but I think you'll find the answers bring about more questions than they answer....people often have more than one horse (for instance, if the quarter horse association has 100,000 horses registered, there may be 30,000 people involved). or have horses of mixed breeds that aren't registered anywhere. Here is a page with some links you can check for answers though:
http://www.ustrotting.com/links/links.cfm?link=1
   Best of luck!
Anne