I"ve been a Life Member of the NRA for 34 years. Since the advent of autoloading pistols, no US civilian has had to hit more than 3 attackers to save himself, in any one encounter. Having to hit more than 2 is very, very rare. the rest flee when you do so. Some have done this, but they did not HAVE to. Bernie Goetz, for instance, didn't have to do more show the 4 subway punks his .38 snub to make them cower away from him, but he pursued and shot them anyway, in a subway car.