http://blog.academyhealth.org/life-expectancy-in-the-us-is-significantly-lowered-by-three-causes-of-injury/

The three injury-causes of death accounted for almost half of the difference in men (1.02 years), and almost 20% of the difference in women (0.42 years). Gun deaths alone accounted for 21% of the gap in men and 4% in women. Car accidents accounted for 13% of the gap in men and 6% in women. Drug poisonings made up 14% of the gap in men and 9% of the gap in women.