The vast majority of bullets only have "To whom it may concern" as the address; tons and tons are launched only to keep people's heads down. I'd be very surprised if many of the rounds launched from door gunners, helicopters, or anything else is actually aimed at an individual combatant.
Add in all the rounds expended for the rest of the Army for training, and don't forget the more specialized troops that will expend several hundred rounds a day .... and the only thing they are hitting is paper targets.
It's sort of like saying the average American expends 1,000 gallons of gas each year but only drives 8,300 for work. It doesn't account for all the other uses that the average person uses his car for.