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Fears over the coronavirus have propelled demand for guns to unprecedented levels, smashing the FBI’s all-time record for monthly background checks processed.

According to the bureau, the National Instant Criminal Background Check System (NICS) conducted 3.7 million screenings in March, the highest number recorded since its inception in 1998. The previous single-month record was 3.3 million in December 2015. The March figures exceed that number by 12 percent.

Because there is no national database of gun sales, NICS background check data is widely regarded as the best available proxy for consumer demand for firearms. However, the numbers do not correspond one-to-one with gun sales for a number of reasons. Multiple firearms can be sold during a single background check, and many checks are processed for permit applications or pawn shop transactions. Also, the system does not capture private sales in states without universal background checks.

Small Arms Analytics, a consulting firm that tracks the gun market, estimates that 2.6 million guns were sold last month based on the background check data, a 85 percent increase over the same period last year. According to its estimate, the surge was largely driven by handgun sales.

The third week of March was the busiest week ever recorded by the FBI’s background check system, which logged 1.2 million checks, according to a ranking published by the FBI. The second and fourth weeks of the month are also among the top 10 busiest weeks. The span of days from March 17 through 21 now hold five of the spots on the agency’s list of the 10 all-time busiest days, with March 20 at Number 1. (The remaining five spots are occupied by Black Friday shopping holidays.) The late-March surge coincided with the declaration of the first statewide stay-at-home order in California, the announcement of travel restrictions at the U.S.-Canadian border, and actor Idris Elba’s coronavirus diagnosis.

Throughout March, news outlets across the country documented gun stores overwhelmed by lines of customers, many of whom were reportedly first-time buyers motivated by fear of societal unrest or xenophobia. At times, the flood of purchases appears to have overwhelmed the federal background check system: The National Shooting Sports Foundation, the trade association of the firearms industry, warned dealers of severe delays in processing.

Nineteen individual states set new background check records last month. Arizona exceeded its previous monthly record by 70 percent, Michigan by 40 percent, and Texas by 13 percent.