The Columbus (OH) Dispatch ran a good article 8/16/05 on "New Chapter in Publishing: Internet bookselling opens door for the little guy." Here are a few snippets:
There are 83,000 publishers in the U.S.
Of those, 70,000 have 10 or fewer titles.
In 2004, 11,500 publishers opened their businesses.
This was a 70% increase over 1995.
195,000 (approx.) new books were published in the U.S. in 2004.
This figure is 114,000 more books than in 1995.
Interesting is that fact that while 114,000 more books were published in the U.S. in 2004 than in 1995, the actual number of books sold annually has remained "relatively flat" in the last decade.
Approx. 2.29 billion books were sold last year.
The Dispatch mentioned Al Greco's book "The Book Publishing Industry" which sounds like a good book to read, for anyone interested in the future of publishing.