More U.S. residents put in requests to buy guns in the month of December 2012 than any other month on record, according to FBI data.

Since 1993, it’s been required that every person who wants to buy a gun from a federal firearms licensee has to pass a background check. That background check is called the NICS, or the National Instant Criminal Background Check, and it is performed by the FBI. The number of checks performed are a pretty good indicator of how many people want to buy guns -- but that doesn’t reflect how many people actually buy guns -- and of course, some are bought on the black market.

November and December are usually the two months that see the highest number of NICS background checks each year, likely because it’s the beginning of hunting season.

The FBI performed more NICS background checks in December 2012 than ever before. January 2013 was also an unusually active month, with a little less than double the number of NICS checks done the previous January. What changed?

When George Zimmerman shot and killed Trayvon Martin, an unarmed teen, on Feb. 26, 2012, it sparked a heated national conversation on gun control -- and brought a slight spike in background checks. But it was the December 14, 2012, massacre of 20 children and six adult staff members at Sandy Hook Elementary School in Newtown, Conn., by 20-year-old Adam Lanza, that elevated the gun control issue to new heights.

With the White House putting gun control on the national agenda in a serious way, Americans worry about possible new infringements on their right to bear arms prompted a spike in gun permit applications, in a way that other recent gun-related tragedies didn’t.

Here’s a look at the number of NICS checks performed, since 1999:

NICS - zimmerman-01
More people put in requests to buy guns during December 2012 than any single month since 1993. IBTimes/Lisa Mahapatra

Click here for the data.