Although the US does not keep official mass shootings stats, a crowd-sourced database has been keeping track.
Reddit users have been using news stories of shootings, where at least four or more people were injured or killed (the FBI recognises an incident as a mass shooting when three or more people were killed), to make their tally.
According to The Mass Shooting Tracker, Robert Lewis Dear Junior’s killing of three and injuring of nine at a Planned Parenthood ofice in Colarado Springs was the 351st case.
Not everyone agrees with the accuracy of The Mass Shooting Tracker; one user MrMember, checked the news links attributed to six stories (#45, #71, #111, #125, #196, and #289) and found that they did not fit the “four or more injured or killed” definition chosen.
Also, not all the injuries or deaths were the result of gunfire according to RT when it checked the links.
As of 9th December, 353 mass shootings were on record- more than one a day. 42% of the shootings, according to The Tracker, caused no deaths. 29% caused one death, and 29% ended with two or more deaths. Only 15 shootings caused more than five deaths.
According to a University of Alabama Criminal Justice Professor Adam Lankford, who defined a mass shooting as being a shooting incident that caused four or more deaths, nearly one-third of all mass shootings in the world occurred in the US between 1966 and 2012, or a tally of 90 incidents. The Phillipins was the country with the second highest number of mass shootings at 18- five times fewer.
An Arizona State University study found that 897 mass shootings occurred between 1998 and 2013 , defining a mass shooting as an event where at least four people died. “roughly 20 to 30 percent of such tragedies appear to arise from contagion,” which is the belief that more shootings arise after one is reported. The University team found “a period of contagion that lasts an average of 13 days.”
A 2011 Gallup poll found that 47% of US adults kept a firearm at home.