Americans are amassing an arsenal.

Last month, the FBI conducted 3.5 million gun-related background checks, a 20% increase from a year before. 1.7 million guns were sold, according to the National Shooting Sports Foundation.

“Firearm sales spiked in March 2020 and have remained at unprecedented levels since. It’s a remarkable feat of firearm manufacturers to keep pace with this blistering demand,” said Mark Oliva, a spokesman for the NSSF.

The Reload, a gun policy news site, reports that “2020 was the best year on record for background checks on gun sales. The first quarter of 2021 was the best quarter in history for gun checks.”

While correlation doesn’t equal causation, a spike in gun violence has coincided with the sales surge. According to the Gun Violence Archive, the number of multiple-victim shootings first rose in April 2020 and has remained high.

Overall, the gun homicide rate in U.S. cities rose somewhere between 35 to 40 percent from 2019 to 2020, the biggest single-year increase on record.

NPR provides analysis on the reasons behind the increased demand for firearms :

Gun sellers across the country said the pandemic and civil unrest over the past year have pushed customers to feel they must take control of their families’ protection. Fears of Congress passing new gun control legislation in the wake of a rash of mass shootings since March are also adding fuel to the buying craze, industry insiders said.

No state has seen more gun sales in recent months than Illinois. According to CNN, “Federal authorities [in Illinois] have completed nearly 4.3 million gun background checks since January, including more than 955,000 submitted last month. That’s more background checks than the next five states combined.”

The glut relates to a large backlog, but a recent crime wave in Chicago might also be driving reactionary gun sales.

As of 2018, the last year there is complete data, the U.S. has 120 firearms per 100 residents. That’s more than double the next highest country – Yemen.

In 2019, 73% of American homicides were gun related. In Canada, that number is 39%. In England, it’s 4%.