A climate of fear and uncertainty drove Americans to gun stores in record numbers last month, setting the FBI’s all-time high for background checks processed.

According to the agency, the National Instant Criminal Background Check System, or NICS, conducted 3.9 million gun background checks in June, the highest volume since it began operating in 1998. The figure eclipses the previous high set in March of this year, and is 71 percent higher than the total from June 2019.

The record spike in gun checks came during a tumultuous month in which state economies began to reopen, widespread protests for racial justice took place in major American cities, and national coronavirus cases resurged to unprecedented levels.

All four weeks of June rank among the six busiest weeks NICS has ever recorded. Over a million checks were conducted during the first week of the month alone.

Checks for handguns, long guns, and multiple guns — the categories that serve as a proxy for sales — increased in every state and Washington, D.C., last month compared to June 2019. In 42 states, the number more than doubled.

Because the federal government does not track gun sales, NICS data is the best available proxy for firearms commerce. But background checks do not correspond one-to-one with sales for a number of reasons: multiple guns can be sold in a single check, and many checks are conducted for purposes other than sales, such as permit applications. NICS also does not account for most private gun sales, which in some states can occur without a background check.

According to Small Arms Analytics, a consulting firm, the June background check figure translates to approximately 2.4 million gun sales. Handguns accounted for a larger share of sales than ever before, continuing several months of steady increases.

In May, The Trace and USA Today reported that gun sales had increased in several of the states that shuttered dealers, as many shops defied stay-at-home orders. All five of those states — Massachusetts, New York, Michigan, New Mexico, and Washington — have now allowed guns dealers to resume some business.