There is no precise data on U.S. gun sales but the FBI file repository provides a good estimate through the number of background checks that it performs from the National Instant Criminal Background Check System (NICS). The NICS requires gun sellers to run the names of potential gun buyers to ensure they aren't disqualified from buying a firearm.

There are gun sales that aren't subject to background checks, so those gun purchases go uncounted. 

The NICS statistics show there were 25,235,215 background checks in 2017, and as of October, there have been 21,245,508 background checks in 2018.

Since 1998, there have been more than 230 million background checks, leading to more than 1.3 million denials.

According to industry research group IBISWorld, gun sales had hit a record high of $9 billion in 2016, a 3.6 percent gain from 2015. The Gun & Ammunition Stores industry over the past five years has grown by 3.8 percent to reach total revenue of $11 billion in 2018. 

Reports have suggested a slowdown in gun sales since Donald Trump was elected president in November 2016. Gun sales tend to surge when there is fear of potential regulations, which was the case during the Obama administration.

Gun production has climbed from 3 million in 1986 to 9 million in 2015, according to the Bureau of Alcohol, Tobacco, Firearms and Explosives.