A gunman at a bar in Thousand Oaks, Calif., Early Thursday, murdered 12 people, including a sheriff's non-commissioned officer responding to the incident. This is the worst shooting incident in the United States since … just over a week.
A debate is ongoing on whether shooting incidents are generally more frequent. In the United States, the rate of violent crime has dropped significantly since the late 1980s and early 1990s, and despite some political rhetoric, it remains almost at its lowest. But there is no doubt that the frequency of mass shootings with a high number of victims – in our case, incidents in which at least 10 people are killed – has increased.
Mother Jones magazine has been closely monitoring mass shootings since 1982, including any incident in which at least four people were killed. Its database includes shooting information, such as the shooter's demographic information, apparent motive, and weapon of choice.
Below is a graph of all Thousand Oaks incidents with at least 10 people killed by the shooter. The horizontal bars indicate the number of days elapsed since the last incident of this type. The longer the line, the more time had passed.
From 1984 to 2004, there was an incident in which at least 10 people were killed about once every four years. In the last four years, there have been eight. There have been four incidents of this type this year alone.
Thousand Oaks shooter reportedly used a handgun, which is not common for recent shootings. Since mass shooting in a movie theater in Aurora, Colorado in 2012, most incidents where at least 10 people have been killed have included the use of more lethal weapons, such as "beating". a semi-automatic rifle (eight out of 10) or a rifle (four out of ten), often in addition to a handgun (seven out of ten).
Since the expiry of the ban on assault weapons in 2004, at least 10 people have been killed, eight of them involving the use of a semi-automatic rifle. According to Mother Jones data, three before Thousand Oaks only used a semi-automatic handgun.