AP Photo/Danny Johnston

In the past two decades, Americans have added approximately 70 million firearms to their private arsenals. There are more gun owners, but they make up a slightly smaller share of the population. Handguns have surged in popularity, and the era of the super-owner is here: roughly half of all guns are concentrated in the hands of just three percent of American adults.

These are among the key findings of a sweeping new survey of gun ownership, provided in advance of publication to The Trace and The Guardian by researchers at Harvard and Northeastern universities. Our two news organizations are partnering to present a series of stories this week based on the survey.

There have been other evaluations of American gun ownership in recent years, but academics who study gun-owning patterns and behavior say the new survey is the most authoritative and statistically sound since one conducted in 1994 by Philip Cook, a researcher at Duke University.

Roughly 100,000 Americans are injured by a gun every year, with a third of those incidents resulting in death. But research into the causes of the violence, methods of prevention, and its toll on families and communities is almost entirely conducted by academics and other private groups.

The Centers for Disease Control and Prevention, the government entity that studies other public health issues, virtually ignores gun violence, owing to legislation widely interpreted as preventing such research.

Otherwise known as chickenshit Congress.

The responses reveal a fundamental shift in gun-owning attitudes. Whereas most owners once considered their firearm primarily a hunting or sports shooting tool, a majority now say they keep guns to protect themselves, their families, and communities.

Accurate reporting on what these people believe. Whether evidence-based facts provoke those beliefs is another question.