336 days, 355 mass shootings

Blacksburg police officers run from Norris Hall on the Virginia Tech campus. Photo / AP

The shooting in San Bernardino yesterday, where 14 people died, brought the number of mass shootings in the US to 355 this year.

It was the third mass shooting in the country since last Friday, when a gunman opened fire on a Planned Parenthood clinic in Colorado, killing one police officer and two civilians.

Carlee Soto reacts as she learns her sister, Victoria Soto, a teacher at the Sandy Hook Elementary School, was one of 26 people killed in a shooting at the school in Newtown. Photo / AP

The figure of 355 comes from the Mass Shooting Tracker maintained by the Guns Are Cool subreddit. The Reddit tracker defines mass shootings as incidents in which four or more people, who can include the gunman, are killed or injured by gunfire.

The Mass Shooting Tracker is different from other shooting databases in that it uses a broader definition of mass shooting - the old FBI definition focused on four or more people killed as part of a single shooting.

Marysville Pilchuck High School. Photo / AP

Speaking after the Colorado Springs shooting last week, President Obama urged Americans to not let this type of violence "become normal". But the data shows this type of incident already is normal. There have been more mass shootings than calendar days so far this year.

The number of mass shootings so far this year has already surpassed the total number of mass shootings in 2014, according to the Reddit tracker. And the pace is well above 2013, when a total of 363 mass shootings occurred.

Sgt. Anthony Sills, right, comforts his wife as they wait outside the Fort Hood Army Base near Killeen, Texas. Photo / AP