Mass shootings by the numbers: More than 350 in 2015

A couple’s gun rampage in San Bernardino, California, on Dec. 2 that left 14 dead came less than a week after a lone shooter at a Planned Parenthood clinic in Colorado killed three.

If it seems like a mass shooting is happening nearly every week in the United States, that's because it's true.

More than 350 mass shootings have occurred in the United States so far in 2015.

Only during one week this year — April 8 to April 15 — has there been no mass shooting, according to Shooting Tracker, an organization that, in the absence of a federal gun violence database, tracks mass shootings through reports in local media.

Defining a mass shooting as an event in which at least four people are shot, there have now been 353 this year.

All told, mass shootings this year have led to 462 deaths.

Besides the rampage in San Bernardino — which is the deadliest single shooting incident in the U.S. since 2012 — three other incidents in 2015 resulted in nine or more deaths: a Roseburg, Oregon shooting on Oct. 1; a Charleston, South Carolina shooting on June 17; and a Waco, Texas shooting on May 17.

Unlike these multiple-fatality incidents, most of the 353 mass shootings reported by Shooting Tracker killed either one person or none: 147 of the incidents resulted in no deaths and 104 in one person dying. Eight mass shootings — including the one in San Bernardino — killed more than five people.

Most mass shootings in the U.S. occur in big cities with high rates of poverty and rampant gun- or gang-related violence.

These events typically get much less media attention than mass shootings in smaller towns or suburban areas or that appear unrelated to gangs or other criminal activity. 

Of the 17 areas that have had four or more mass shootings this year — for a total of 87 between them — all are cities with populations of more than 200,000. Six of the 17 cities are big, with more than 2 million residents. 

Chicago this year has the highest number of reported mass shootings — 14, resulting in a total of 10 deaths. These are one part of the sky-high rate of gun violence in the city, which has seen gun arrests increase by 22 percent this year and a total of 2,200 shootings amid 6,500 seizures of illegal guns.

Baltimore, which comes second in the number of reported mass shootings this year, with 10 incidents resulting in eight deaths, has a similar stark problem with gun violence. The city this year experienced one of its deadliest summers on record and is on pace to have more than 300 homicides, the most in the city since 1999.

Houston has had five mass shootings this year, but the highest number of deaths from such incidents — 13. That is second only to San Bernardino.