The FAA has issued nearly 23,000 drone pilot licenses in just three months

Since the Federal Aviation Administration clarified the rules for commercial versus recreational drone flying at the end of August, nearly 23,000 people have become licensed commercial drone pilots, according to the FAA.

The agency released its rules for commercial drone operators on Aug. 31, requiring pilots who fly for work or business to pass a test and become certified. The FAA says that, between Aug. 31 and Dec. 9, over 28,000 people applied to become a professional drone pilot and 22,959 licenses were issued.

That means more than 300 people a day (that’s weekdays) across the United States have become certified drone operators in roughly three months.

The number of certified unmanned aircraft pilots, however, pales in comparison to the number of drones registered with the FAA, which was over 550,000 as of September and amounts to an average rate of 2,000 drones registered a day.

Hobbyists — amateaur photographers or those flying for fun who aren’t making money from operating a drone — don’t need to get certified. But anyone flying an aircraft that weighs more than half a pound does need to register the drone with the FAA, which can be done online.

Drones are now being used in all kinds of industries, from real estate to cell tower inspection. In October, President Obama awarded a grant of $2.2 million to train coal miners how to professionally fly drones in southwest Virginia. The emerging global construction drone market is valued at $127 billion, according to research published in May from PwC.

The aeronautical knowledge test to become a certified drone pilot does require some studying. Pilots have to go to a local testing center that offers the drone pilot certification; it usually costs about $150 to take the exam, according to the FAA.

This article originally appeared on Recode.net.