The report, which draws on official data, survey data and other measures for 230 countries, finds that global firearm ownership is heavily concentrated in the United States. In 2017, for instance, Americans made up 4 percent of the world's population but owned about 46 percent of the entire global stock of 857 million civilian firearms.
With an estimated 120.5 guns for every 100 residents, the firearm ownership rate in the United States is twice that of the next-highest nation, Yemen, with just 52.8 guns per 100 residents. In raw number terms, the closest country to the United States is India, with 71.1 million firearms in circulation. These numbers do not include firearms owned by law enforcement agencies or militaries.
On gun ownership, the United States stands out among the world's wealthiest nations, with an ownership rate more than three times higher than the rate in the next-highest country, Canada. The gun ownership rate in the United States is more than six times higher than the average among similar wealthy nations in the Organization for Economic Cooperation and Development.
The Obama years were a boom time for America's gun manufacturers, which doubled their annual output between 2009 and 2013, fueled in part by fears of a federal crackdown on gun ownership that never materialized. “In the United States alone civilians acquired at least 122 million new or imported firearms during the period 2006–17,” the Small Arms Survey found.
A separate Harvard-Northeastern study published in 2016 found that 3 percent of American adults (individuals in this case, not households) own half the nation's firearms. Combined with the latest Small Arms Survey estimate, that would mean that 3 percent of American adults own nearly one quarter of the world's civilian firearms stockpile. It's worth noting, however, that the Harvard-Northeastern study, which was based on a survey of gun owners, estimated a much lower number of guns in circulation: 265 million as of January 2015.
Because there is no official tally of American gun ownership, there's a margin of error around any estimate of either gun ownership or the number of guns in circulation. Some gun owners may be disinclined to answer survey questions, for instance, which would result in an undercount of the number of households and individuals owning guns.
Similarly, any estimate of the number of guns in circulation has to make an assumption about attrition — the number of firearms that are destroyed or otherwise become unusable in any given year. The number of guns in circulation could be subject to overcount or undercount, depending on how researchers model the effects of attrition.
Regardless, the big-picture trends are not in dispute. Measured in rates or in raw terms, the United States is the civilian gun capital of the world.