If this swine flu is an “optimal” flu, it could kill 100,000-200,000 Americans. But typically, 30,000-50,000 Americans die of ordinary flu every year.
However, H5N1 Avian flu holds the prospect of killing 30,000,000 Americans. It is a whole ‘nother ballgame.
That sounded way high when I first read your post. Then I checked it out, and it's not:
http://www.cdc.gov/od/oc/media/pressrel/r030107.htm