America's unique problem with gun violence, in one chart

America has six times as many firearm homicides as Canada, and 15 times as many as Germany:

This chart, compiled using United Nations data collected by the Guardian's Simon Rogers, shows that America far and away leads other developed countries when it comes to gun-related homicides. Why? Extensive reviews of the research by the Harvard School of Public Health's Injury Control Center suggest the answer is pretty simple: The US is an outlier on gun violence because it has way more guns than other developed nations.