Three generations of Apple iPhones accounted for four of the top five most traded-in devices in the fourth quarter, with the iPhone 6 leading the way by a wide margin, a new information from Hyla Mobile shows.

According to a Hyla Mobile infographic that compiled data from Hyla, Gartner, IDC, and Deloitte for the North American Market, the iPhone 6 topped the list of U.S. smartphone trade-ins during the fourth quarter, with 273,764 devices turned in by consumers. The iPhone 6 Plus and iPhone 5S were nearly tied in second and third place with 96,992 and 95,155 devices traded in, respectively, while the iPhone 6s brought up fourth place with 60,285 devices swapped. The only device in the top five not from Apple was Samsung’s Galaxy S5, with 34,125 devices traded.

Representatives for T-Mobile, Sprint, and AT&T on Tuesday declined to disclose carrier-specific numbers.

But the top traded devices weren’t necessarily the ones with the highest trade-in value. Brand new iPhone 7 smartphones aside, the Moto Z Force Droid brought consumers the most dime at $280, followed by the iPhone 6s Plus at $262.99 and the Samsung Galaxy S7 Edge at $251.69. The average trade-in value of an Apple iPhone was $156.17, compared to $72.19 for an Android smartphone.

Another key metric Hyla shed light on was the age of used devices that were traded in, which averaged out to 2.42 years. That figure was slightly less for iPhone users, at 2.39 years, while slightly higher for general smartphone users at 2.53 years.

According to Hyla Mobile CEO Biju Nair stats like these – and the fact that Compass Intelligence estimates indicate more than 125 million devices were recycled in 2016 – help show the mobile refurbished market is “poised for growth.”

Nair said three main factors will drive the growth in the used mobile market, including demand in developing markets, the growth of mobile device insurance, and growth in the certified pre-owned market.

“In low and mid-income countries, access to Mobile Devices is higher than access to water and electricity,” Nair noted. “This provides a distribution opportunity for higher end functional, yet affordable, used devices.”

Additionally, as the mobile insurance market grows, carriers and OEMs will demand more high-quality refurbished devices to serve as loaners during repairs or replacements for broken devices, he said.