This year’s latest mass shooting occurred on Friday, when a gunman entered a Planned Parenthood clinic in Colorado Springs, killing three people and injuring nine others. According to news reports collected by a reddit community that tracks mass shootings, there have been 351 such incidents in 2015.

“The reddit tracker defines mass shootings as incidents in which four or more people, including the gunman, are killed or injured by gunfire,” writes Christopher Ingraham for The Washington Post. “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 murdered as part of a single shooting.”

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