The United States experienced yet another mass shooting this week, when a gunman killed 12 people at a naval shipyard in Washington, DC. There have been more than 60 gun-related slaughters in the country since 1982, with the vast majority being committed by individuals using weapons purchased legally, according to Mother Jones.

The total number of mass shootings (defined as those involving at least four victims in a single incident) from 1982 to 2012 was 62. The number of guns used in these attacks was 143, more than 75% of which were obtained legally.

The firearms included dozens of assault weapons and semi-automatic handguns with high-capacity magazines, such as those used by Jeffrey Weise (.40-caliber Glock) in Red Lake, Minnesota, in 2005; James Holmes (AR-15 assault rifle) inside a Colorado movie theater last year; and Adam Lanza (.223 Bushmaster semi-automatic assault rifle) in Newtown, Connecticut, in 2012.

More than half of the 62 shootings took place either at a workplace (20) or a school (12).

The other 30 tragedies occurred in various locations, including shopping malls, restaurants, and religious and government buildings.

Forty-four of the killers were white males.

Only one shooter was a woman: Jennifer San Marco (Goleta, California, in 2006.)

The average age of the killers was 35.

The youngest shooter was only 11 years old: Andrew Douglas Golden (Jonesboro, Arkansas, in 1998.)

“A majority were mentally troubled—and many displayed signs of it before setting out to kill,” Mark Follman, Gavin Aronsen, and Deanna Pan wrote for Mother Jones.

-Noel Brinkerhoff

To Learn More:

A Guide to Mass Shootings in America (by Mark Follman, Gavin Aronsen, and Deanna Pan; Mother Jones)

Public Mass Shootings in the United States: Selected Implications for Federal Public Health and Safety Policy (by Jerome P. Bjelopera, Erin Bagalman, Sarah W. Caldwell, Kristin M. Finklea, and Gail McCallion; Congressional Research Service) (pdf)

Murder Rate Down, but Random Mass Shootings Up (by Matt Bewig, AllGov)          

Is the AR-15 becoming the Weapon of Choice for Deranged, Young Male Mass Murderers? (by Noel Brinkerhoff, AllGov)