Pro-gun advocates prepare for a 'mock mass shooting' at the University of Texas in 2015, a demonstration intended to show the need for firearms on campus.

There are hundreds of millions of guns in the United States—enough, according to several estimates, for every American civilian adult to own more than one.

But actual gun ownership is far more lopsided than that.

A sweeping new survey by researchers at Harvard University and Northeastern University finds that roughly half of the nearly 300 million firearms in the United States are concentrated in the hands of a tiny sliver of the U.S. population: Just 3 percent of American adults own some 130 million guns, according to The Trace and Guardian US, two news organizations that first reported on the survey. (The full survey has not yet been released; Guardian US and The Trace reported plans to publish a series of stories about the findings throughout the week.)

This portrait of gun ownership represents the equivalent of about 17 guns per person among a group of “super-owners,” the 7.7 million Americans who own between eight and 140 guns each.

Super-owners are emerging at a time when the number of guns in the country is rising—the nation’s stock of firearms has swelled by some 70 million guns since 1994 —while the percentage of gun owners in America has dipped. In other words, there are now more guns to go around in a shrinking population of gun owners. (About one-quarter of Americans say they own a gun, though more than one-third of Americans report living in a house where there is a firearm.)