After Thursday’s mass shooting at Umpqua Community College claimed ten lives in Roseburg, Oregon, officials revealed that Christopher Harper Mercer, the gunman behind the attack, had owned a stockpile of 14 firearms. The number elicited shock from the gunman’s father live on CNN: “How was he able to compile that kind of arsenal?” Ian Mercer asked. But as it turns out, owning ten or more firearms isn’t all that uncommon: According to a forthcoming study of gun ownership conducted by Harvard researchers, more than six million Americans already do. In other words, there are more people in America who own ten or more guns than there are residents of Denmark.

The figures come from Dr. David Hemenway, the director of Harvard’s Injury Control Research Center. In an online survey of 3,000 people conducted this year, Hemenway and his team found that some 22 percent of Americans are gun owners. Eight percent of those gun owners (or two percent of American adults) can claim an arsenal of 10 or more firearms, while 25 percent own five or more guns.

Hemenway says the concentration of guns in a small amount of hands means that fewer people have access to America’s estimated 300 million firearms. “We’re told all the time that there are enough guns for every person in the United States,” he tells The Trace. “And that’s probably true, but the issue is, in part, everybody doesn’t have those guns and everyone doesn’t have easy access to those guns. That’s actually very good for suicides and gun accidents.”

But the numbers also spark questions about why millions of Americans feel the need to own so many weapons. “These are people who do buy guns and have a lot of them,” he says. “So we have to wonder, who are these people and why do they have so, so many guns? What’s the purpose of it? And are they really responsible?”

The Harvard researchers are still parsing their survey, which is expected to be released next year. Among the statistics they’re digging into are the demographics of those in the 1o-plus guns club. Im sure — or I bet — theyre white males,” Hemenway says. By far, the most likely person to be a gun owner is a white male, so it would be surprising if it was somebody else.

Public health researchers are interested in gun collection totals because of the risks that level of gun ownership creates. Hemenway specifically emphasized the need for owners of multiple guns to take special precautions in securing their guns. These people have a special responsibility to make sure that they lock their guns carefully,” he said. “They are real targets for burglars.”

[Flickr user Keary O.]