The TSA has been very busy lately.

One day in February, the agency discovered 21 firearms at U.S. airports—the most weapons ever seized in a single day.

The firearms were discovered in Asheville, North Carolina and bi-airport hubs like Washington’s Dulles Airport.

But there are more serious numbers to report.

Last year, the TSA seized 3,391 firearms at airports across the U.S.

That’s a whopping 28 percent increase from 2015.

Some analysts think the increase is due simply to more people traveling last year.

Or perhaps it’s because the TSA is changing its inspection protocols and slowing down the conveyor belts to scan carry-on bags.

Do you want an even scarier statistic?

Of the 21 weapons seized on that day in February, all but 1 were loaded.

For more information about airports and travel safety, check out:

• Some of  the Craziest Items Seized by the TSA
• The Importance of Following Emergency Landing Procedure
• What You Should Know About State Department Advisories

Keep reading for more travel tips.