I didn't do quite as much research for this one, but here's CDC's "leading causes of death" table for 2013.[1] #1 for 25-34: unintentional injury with 16,209 d

I didn't do quite as much research for this one, but here's CDC's "leading causes of death" table for 2013.[1] #1 for 25-34: unintentional injury with 16,209 deaths. #2 for 25-34: suicide, 6,348 deaths (but if you don't engage in risky behavior, you wouldn't commit suicide, right?) #3 for 25-34, homicide, 4,236 deaths - the vast majority of these are _not_ in mass-shooting incidents, of course. #4 is cancer (3,673 deaths) and #5 is heart disease (3,258 deaths). By the way, for felony homicides, the majority (69.1%) are perpetrated against a single victim[2]. [1] (PDF warning): http://www.cdc.gov/injury/wisqars/pdf/leading_causes_of_death_by_age_group_2013-a.pdf http://www.cdc.gov/injury/wisqars/pdf/leading_causes_of_deat... [2]: https://www.fbi.gov/about-us/cjis/ucr/crime-in-the-u.s/2011/crime-in-the-u.s.-2011/tables/expanded-homicide-data-table-4 https://www.fbi.gov/about-us/cjis/ucr/crime-in-the-u.s/2011/...