Mass shootings have occurred in the United States with increasing frequency over the past 14 years, with 486 people killed in 160 incidents, according to a Federal Bureau of Investigation analysis released on Wednesday.
There were an average of 16.4 active-shooter incidents from 2007 through 2013, more than double the 6.4 average from 2000 to 2006, the report found.
Active shootings, which the report defined as incidents not directly linked to gang violence or drugs and where police and citizens had the time to influence the outcome, occurred most frequently in places of business, which saw 46 percent of the incidents, followed by schools, where 24 percent occurred.
The report was released a day after a man who had recently been fired from his job at a United Parcel Service Inc distribution center in Birmingham, Alabama, shot dead two supervisors at the site before turning the gun on himself.
That ending, the gunman taking his own life, was a common one in the events the FBI analyzed, with 40 percent of the shooters turning their guns on themselves. Police shot and killed the attacker in 13 percent of the cases analyzed.
The deadliest incidents were the 2007 shooting at Virginia Tech University, where 32 people were killed, and the 2012 massacre at Sandy Hook Elementary School, where 27 died excluding the gunman.
FBI officials noted that many shooters had studied past incidents, particularly prominent ones like Virginia Tech, Sandy Hook or the 1999 attack at Columbine High School in Colorado, where two gunmen killed 12 students and a teacher.
That incident was not included in the 160 counted by the FBI. (Reuters)