The Numerically Significant Answer

"Gun owners who say they belong to the NRA tend to own more guns, on average, than gun owners who don’t belong to the NRA: About half (52%) say they own five or more guns, compared with 24% of non-NRA members (38% of nonmembers say they own only one gun). NRA members also hunt and shoot with more frequency than gun owners who aren’t NRA members: 50% say they go hunting often or sometimes, compared with 30% of nonmembers; 66% of NRA members go shooting often or sometimes, versus 49% of nonmembers."

Pew Research Center

National Rifle Association protestations aside, along with the great number of Americans who support the 'right to bear arms' enshrined in the U.S. Constitution, while guns may not kill, people do as they claim, the easy access to and great proliferation of guns owned by citizens is indeed responsible for the reputation the United States has earned as the killing capital of the world -- by guns, wielded by people who own them. A lot of people. A lot of guns.

A body of research exists -- and it is growing -- affirming that though Americans are not inherently violent, their accessibility to firearms results in deadly-violent incidents of unsurprising consistency and frequency of occurrences. Comprised of 4.4 percent of the global population, Americans own 42 percent of the guns circulating in the world, with over 300-million guns in the United States, averaging to one for every man, woman and child in the population.

Research shows that 31 percent of mass shooting gunmen worldwide were American, according to a 2014 study by the University of Alabama's Adam Lankford. Yemen alone among other nations has a higher rate of mass shootings among nations with over ten million people. After the United States, Yemen qualifies as the world's second largest gun ownership nation. A massively poor, undeveloped nation in comparison to the world's premier leadership nation, advanced in technology, research and commerce. 

In his research, Dr. Lankford found confirmation that the rate of gun ownership correlates unfailingly with the number of mass shootings experienced. And nor can any of this be attributed to mental health, since Americans are no more plagued with mental  health issues than any other country. Health care spending in mental health is comparable with other wealthy nations, with a 2015 study estimating 4 percent of American gun deaths attributable to mental health issues.

The gun homicide rate in America in 2009 was 33 per million in comparison to Canada's 5 per million and the  United Kingdom's 0.7 per million, numbers corresponding to differences in gun ownership. A 1999 study by Franklin Zimring and Gordon Hawkins of the University of California concluded that the U.S. is no more prone to crime than other developed countries. But U.S. crime distinguishes itself by being infinitely more lethal.

Gun-related deaths in 2013 included 21,175 suicides, 11,208 homicides and 505 deaths inadvertently caused by accidental discharge. Guns in the hands of curious and innocent children have proven to be disastrously lethal; in some instances killing other children, and in others their own parents. Accessibility is the key. In comparison, only 13 deaths attributable to guns were registered in that same year in Japan, smaller population by two-thirds aside.

The second-highest gun ownership rate of any developed country is in Switzerland where the gun homicide rate in 2004 was 7.7 per million people; a high enough number, totally reflecting the number of weapons circulating in society, yet still well under the U.S. rate. Switzerland has more stringent gun laws, with a higher bar set to secure and maintain a license and for selling guns as well as types that can be possessed by Swiss citizens.

That people have an inherent right to own guns is shared with the United States by Guatemala and Mexico, with resulting lax regulations for gun ownership. Relatively unregulated gun ownership is deemed to be a value whose cost to society in gun-related deaths is a worthwhile exchange. "In retrospect Sandy Hook marked the end of the U.S. gun control debate", wrote British journalist Dan Hodges, of the 2012 attack where 20 children and six adults were shot to death at a Connecticut elementary school.

"Once America decided killing children was bearable, it [the debate] was over."

At least 23 weapons were found in the Las Vegas hotel suite of the gunman who targeted an outdoor concert on Sunday night, killing 59 people, including himself, and injuring more than 500 others. Authorities found 19 more firearms, and hundreds of rounds of ammunition, in the home of the gunman, Stephen Paddock     A federal law enforcement official said the guns Stephen Paddock used to carry out the shooting in Las Vegas included AR-15-style rifles. Credit John Moore/Getty Images