Just how popular have drones become? According to The NPD Group’s Retail Tracking Service, drone sales have grown 224 percent year-over-year (ending April 2016) to nearly $200 million. And over the past six months (ending April 2016), sales growth has accelerated to more than four times higher than the same time period in 2015.

With sales numbers up 224%, it appears mandatory drone registration hasn’t been much of a drag. Of course, in December 2015 the FAA launched mandatory drone registration for anyone who owns a drone weighing more than 0.55 lbs. but less than 55 lbs. flying outdoors for hobby or recreation. Failure to register a drone can result in civil penalties up to $27,500, and criminal penalties for failure to register can include fines of up to $250,000. To register, you’ll need to provide your name, home address and e-mail address.

The FAA recently released its database that shows how many drones owners are registered in each city, state, or zip code. At the time the database was released, there were 461,433 registered hobbyist drone owners in 39,471 zip codes – that’s an average of just under 11.7 registered drone owners per zip code, according to the database.

NPD said that DJI, as expected, continues to be the US market leader with a 49% share of the market. Parrot, maker of the Bebop and Bebop 2 drones, is second at 19%, with Protocol, Yuneec, and 3D Robotics rounding out the top five.

According to NPD, drones with 4K cameras accounted for more than one-third of dollar sales in the 12 months ending April 2016, while drones with built-in GPS accounted for 64 percent of revenue. Additionally, drones with an average price greater than $500 accounted for 56 percent of dollar sales in that same time period. The average drone sold for more than $550 in April, giving drones one of the highest average prices of all categories in technology at retail.

“The drone category is continuing to take shape as new products and features such as 4K cameras, Bluetooth and built-in GPS, reveal an expanding range of use cases. The market is maturing in that respect,” said Ben Arnold, executive director, industry analyst for The NPD Group. “The continued interest around unmanned aerial systems and an expanding retail footprint point to a strong 2016 and 2017 as a result.”

Drones proved to be a compelling holiday item with the 2015 holiday season seeing unit sales increasing 445 percent from the prior holiday season. Accompanied by high consumer interest and competitive prices, sales for December alone were 273 percent higher.

“It’s not surprising that drones were highly sought after during last year’s holiday season,” said Arnold. “But even after the holidays, NPD’s consumer research indicates drone purchase expectations remain high, especially among younger consumers. This points to continued growth and healthy demand for the category.”