[nagdu] Final correction

[Angie Matney]

Whew! I'm numerically challenged this evening. (I have spent too much time with my own research paper.) The 9,000 figure was for only guide dogs. Here is an actual passage from the article. That way, I won't mess it up:

Our best estimate 
is that 4,000 hearing dog and 4,000 service dog teams are 
currently working. Combining the figures for guide, hearing and 
service dogs, a total of 17,000 assistance dogs are currently 
working in the United States (Eames and Eames 1997).