This past June, after a gunman walked into a Charleston church and killed nine people, President Obama delivered a speech that has since become familiar.
"At some point, we as a country will have to reckon with the fact that this type of mass violence does not happen in other advanced countries," he said. "It doesn't happen in other places with this kind of frequency. And it is in our power to do something about it."
Obama would make that speech two more times more this year, including after a gunman killed nine people at a community college in Roseburg, Oregon, and the San Bernardino shooting earlier this month in which 14 people were killed.
There is no single agreed-upon national definition for what makes a mass shooting, so the total number this year varies depending on whom you ask. FBI defines a mass murder as an incident in which someone kills four or more people. Some publications that have been tracking mass shootings, like Mother Jones and USA Today, use the FBI's definition.
But other groups say that the FBI's definition is too narrow. The organizations Mass Shooting Tracker and Gun Violence Archive define mass shootings as any incident in which one in which four people were shot by a bullet, regardless of whether they died or not. They argue that this definition more accurately describes gun violence in this country because a mass shooting should count people who were shot, even if they don't die.
"It was very clear that the big shootings where many were killed got the lion's share of attention and those where folks were 'just shot' were often time ignored," said Mark Bryant, the executive director of GVA. "It never made sense to look at a shooting where 17 were 'just' injured as any less of a mass shooting as one where four or five were killed."
According to Mass Shooting Tracker, there were 365 mass shootings in 2015 as of December 21 (that total also varies slightly depending on whether you count the shooter in the total dead — historically Mass Shooting Tracker has, but will no longer after partnering with Gun Violence Archive this month).
Mass Shooting Tracker uses crowdsourced reports of mass shootings, which are then verified through news reports. Their data has been widely cited and is the source for the often-repeated claim that there has been an average of one mass shooting per day in 2015. According to GVA's tally, there were 45 more mass shootings this year than last.
Here is what this year looked like in mass shootings.