Complex sentence: The average number of rounds expended by U.S. military snipers to kill one enemy soldier was 1.3 rounds, which is a cost-difference of $23,000 per kill for the average soldier, vs. $0.17 per kill for the military sniper.
Split into simpler sentences: The average number of rounds expended by U.S. military snipers to kill one enemy soldier was 1.3 rounds. That's a cost-difference of $23,000 per kill for the average soldier, vs. $0.17 per kill for the military sniper.