Here is another link with supporting data.

http://www.neiassociates.org/caliber.htm

The 357 magnum, 9mm, 45 and 40 are all 90+% on one stop shots.

The .40 is the winner but only by a tiny percentage.

IMHO, there is nothing wrong with carrying a nice compact 9mm or 40 as both have decent stopping power and more capacity than a typical 45.