In 2015, there were more days with a mass shooting than days without a mass shooting.
December 2 marked the deadliest day of the year with the shooting in San Bernardino, California, that killed 16 and injured 19. There was also a second reported mass shooting on December 2 in Savannah, Georgia, that killed one and injured three.
Not a single month in 2015 was free from a mass shooting. Overall, 468 died from 372 mass shootings in 2015. June witnessed the greatest number of mass shootings of any given month, and June 13 saw the greatest number of mass shootings — six in all.
Compared with 2014 fatalities, the 468 deaths in 2015 mark a 22.2 percent increase from the 383 in 2014. Additionally, there were 37 more mass shootings in 2015 than in 2014. But it's hard to identify a definitive trend when it comes to the frequency and deadliness of mass shootings, as 2013 remains deadlier than both 2014 and 2015 with 502 reported fatalities from 363 mass shootings.
These numbers come from Mass Shooting Tracker, a crowdsourced database that has tracked mass shootings since 2013. The database defines a mass shooting as an event in which four or more people were shot (not necessarily killed), and, as with any crowdsourced database, it’s likely missing data or has incomplete records. I used the database to create this calendar of all known mass shootings that have occurred in 2015.
It's important to note that there is not one universally accepted definition of what constitutes a mass shooting. Mass Shooting Tracker defines a mass shooting as an event in which four or more people were shot, but others have disputed its methodology. Some counts, like the one compiled by USA Today, only track mass killings, or events in which four or more people were killed. Mother Jones also maintains a database, which like USA Today only tracks events in which four or more people were killed, but Mother Jones excludes shootings related to "gang activity, armed robbery, or domestic violence."
On the whole, regardless of differences in classification, deaths from mass shootings make up a small fraction of deaths from gun violence. The Centers for Disease Control and Prevention estimated that in 2013 alone, 33,636 people died in firearm deaths, or 92 people every day. But looking at 2013 data from the Mass Shooting Tracker, only 502 of those deaths — or 1.5 percent — were connected to mass shootings.
Most gun deaths in the United States (21,175 of 33,636 in 2013) are suicides. And most non-suicide deaths (11,208) are homicides. The rest are classified as accidents and police shootings. And while it's true that homicide rates have reached historic lows, no other developed country in the world has the same rate of gun violence as America. The US has nearly six times the gun homicide rate as Canada, more than seven times as Sweden, and nearly 16 times as Germany, according to UN data compiled by the Guardian.
This is not to say that Americans shouldn't care about mass shootings. But mass shootings are only one part of the equation in America's ongoing problem with gun violence.