There have been at least 44 school shootings on K-12 or college campuses in 24 states — an average of more than three a month — since the deadly 2012 attack at Sandy Hook Elementary School in Newtown, Conn., according to a new analysis. Twenty-eight people have died and 37 have been injured.

Twenty children and six adults working at Sandy Hook were killed in the December 2012 assault in Newtown, leading to renewed calls around the nation for Congress to take action to prevent more gun violence. Legislators did nothing.  Shannon Watts, founder of Moms Demand Action for Gun Sense in America, which did the analysis along with the national organization called Mayors Against Illegal Guns, said in a statement:

“Parents in communities across the country live in fear. An estimated 90 percent of school districts have tightened security since Newtown – installing metal detectors, surveillance cameras, and bullet-proof glass. Schools now routinely have lockdown drills reminiscent of Cold War air raid drills.”

Mayors Against Illegal Guns was co-founded in 2005 by then New York City Mayor Michael Bloomberg and then Boston Mayor Thomas Menino.

The analysis says:

*In the fourteen months since the mass shooting in Newtown, CT, there have been at least 44 school shootings including fatal and nonfatal assaults, suicides, and unintentional shootings — an average of more than three a month. In the first six weeks of 2014 alone, there were 13 school shootings including one eight-day period in which there were four shootings in K-12 schools.
*These school shootings resulted in 28 deaths and 37 non-fatal gunshot injuries. In 49 percent of these incidents at least one person died.
*Of the K-12 school shootings in which the shooter’s age was known, 70 percent (20 of 28 incidents) were perpetrated by minors. Among those shootings where it was possible to determine the source of the firearm, three-quarters of the shooters obtained their guns from home.
*In 16 cases — more than a third of all incidents — at least one person was shot after a schoolyard argument or confrontation escalated and a gun was at hand.
*The shooters ranged from 5 to 53 years of age.
* The 44 school shootings occurred in 24 states across the country. Sixty-four percent of the shootings took place at K-12 schools and thirty-six percent took place on college or university campuses. 
*Thirty-three shootings (75 percent) involved an assault or homicide; of these, 12 incidents resulted in at least one homicide. In 11 incidents, the shooter attempted or completed suicide — in 4 incidents after shooting someone else. In 4 other incidents, no one was injured.
*Many of the students who perpetrated these shootings had easy access to guns at home. In several cases, investigators declined to comment on how the child obtained a firearm because the incidents are under active investigation. But in the eight incidents where the source of the firearm was known, three-quarters of the shooters used a gun they obtained from home. This includes three cases where a minor used a gun to attempt or complete suicide in his school.