http://www.worldlifeexpectancy.com/usa-cause-of-death-by-age-and-gender

http://www.cdc.gov/nchs/data/dvs/LCWK9_2013.pdf

http://www.medicine.ox.ac.uk/bandolier/booth/Risk/leading.html

要担心生命安全，自己看看去。
forbes “More than 32,000 people per year are killed by guns in the United States — at least.”

http://www.forbes.com/sites/dandiamond/2015/08/26/americas-gun-violence-problem-in-three-charts/

NPR 说 每10万 3.55。

http://www.npr.org/sections/goatsandsoda/2015/12/07/458815891/the-u-s-is-a-world-leader-in-gun-deaths

不知道他们怎么来的数据。反正是声称有source过来。