A question from Yahoo! Answers:
What is the total number of franchisors (ie: franchise opportunities) in the United States?
I would guess, about 3,000. Franchising has experienced an expansion in 1970s and early 1980s, but then the growth began to slow down. In 1972, there were 909 franchisors in the U.S.; in 1986, 2,177; by 1995, the number increased to 2,618.
There is a book called The Franchise Annual, which is published annually and contains data and profiles of all franchises operating in the U.S., Canada, and internationally. Ask your local public library if they have a copy (they most likely do).