In response to the Wednesday night shooting at a black church in Charleston, South Carolina, President Barack Obama highlighted a troubling fact: America has far more gun violence than its developed peers around the world.

"This type of mass violence doesn’t happen in other advanced countries," Obama said on Thursday. "It doesn’t happen in other places with this kind of frequency. And it is within our power to do something about it. I say this recognizing that the politics of this town foreclose a lot of those avenues. But it would be wrong for us not to acknowledge it."

Obama is right: gun violence is way more common in the US than in its developed peers — and it’s not even close. This chart, compiled using United Nations data collected by the Guardian’s Simon Rogers, shows that America far and away leads Canada, Japan, and several European counterparts in gun homicides:

Gun violence is much more prevalent in the US than among its peers

Rate of gun-related homicides per 100,000 population in the US, Canada, Japan, and parts of Europe

But why does the US have so many more gun homicides than other advanced countries? One possible explanation: Americans are much more likely to own guns than their peers around the world. And the empirical research shows places with more guns have more homicides.

According to survey data compiled by Rogers, the US had 88.8 guns per 100 people in 2007 — compared with 54.8 in the second-closest country, Yemen. Reddit user Phillybdizzle mapped Rogers’s data, showing just how much the US stands out compared to the rest of the world:

Phillybdizzle/Reddit

Criminal justice experts widely recognize this is a result of cultural and policy decisions that have made firearms far more available in America than in most of the world. And Obama wants the general public to recognize that, too — and push lawmakers to do something about it.

Places with more guns have more homicides

Protestations of gun rights supporters aside, public health researchers who study firearms generally agree that increased firearm ownership rates are associated with higher rates of homicide. The Harvard School of Public Health’s Injury Control Research Center is a great resource here. It notes that a wide variety of methodologies show guns as a risk factor for homicide in the US and other high-income countries. Developed countries with more guns generally have more homicide; states within the US with more guns have more homicide; people with access to guns — particularly women — are more likely to be victims of homicide than those without access.

It’s important to note, however, that all these studies show an association, rather than causation. It could be that areas with more guns are more prone to murder for other reasons. But the fact that the finding holds up no matter how you approach it is suggestive, and most experts think the relationship is at least partially causal. "Within the United States, a wide array of empirical evidence indicates that more guns in a community leads to more homicide," David Hemenway, the Harvard Injury Control Research Center’s director, wrote in his book Private Guns, Public Health.