Hobbyists have registered over 181,000 drones since the Federal Aviation Administration opened a new registration system on Dec. 21.

FAA administrator Michael Huerta said that the database, created following a series of potentially dangerous incidents involving drones flying in restricted airspace, has been a success. The high numbers of people signed up shows that many people are obeying the new federal rule that requires them to register or face a penalty of up to $27,500.

“Simply put, registration is all about safety,” Huerta said during a speech at the annual Consumer Electronics Show in Las Vegas. “It provides us with a key opportunity to educate the new generation of airspace users that as soon as they start flying outside, they’re pilots.”

SIGN UP: Get Data Sheet, Fortune’s daily newsletter about the business of technology

To register their drones, hobbyists must submit their names, home addresses, and email addresses into the online system and acknowledge that they have read the FAA’s safety guidelines. They then have to pay a $5 dollar fee and obtain a registration number that they must place on the body of their drone.

People who register before Jan. 20 get their $5 refunded. The fee covers all drones they own for a three-year period.

The federal government’s idea to require drone owners to register had faced intense criticism from some drone enthusiasts and manufacturers. Some zeroed in on the cost, calling it a “drone tax,” while others argued that local and state governments might complicate matters by creating their own regulations.

Huerta acknowledged the possibility of confusion and said the FAA had given states and municipalities that are considering laws or regulations some guidance. Local laws shouldn’t conflict with the federal government’s rules, he said.

Despite Huerta’s optimism about the registration system, the number of people signed up is still relatively light compared to overall ownership numbers. During the holidays alone, retailers were expected to sell nearly 400,000 drones, according to the Consumer Technology Association.

WATCH: For more on CES see our Fortune video:

This year, the industry group expects sales of one million drones that meet the minimum weight requirements for registration, or 145% more than in 2015, the association said.

As for drone used by businesses, Huerta said he expects the FAA to finalize rules for commercial operations by the end of spring. Currently, companies must be approved on a case-by-case basis. The FAA has granted over 3,000 permits to businesses, up from 1,000 through early 2015.

In addition talking about the registration system, Huerta said the FAA had introduced a new drone app called B4UFLY for iOS devices that people can use to identify airspace where drones are prohibited. He said an Android version is also available for testing, but that is not yet officially released.

“We expect that B4UFLY will help heighten public awareness about what it means to operate unmanned aircraft safely,” said Huerta.