Apple iPhone owners in the United States are apparently pretty eager to purchase apps, with the average spending in 2017 having seen a substantial increase from the year before. According to a new study by intelligence firm Sensor Tower, U.S. iPhone users are buying lots of apps, with an average of $58 spent on in-app purchases and premium apps last year—23 percent more than 2016.

According to Variety, around $36—more than half of the $58 average total—was spent on mobile games, which is an increase from 2016’s $32 per device. In an era where Epic Games’ Fortnite is breaking records, and the iPhone X’s augmented reality support is helping developers create new exciting apps, these numbers certainly make sense. To put this in an even clearer context, users reportedly spent over $1 million on in-app purchases during the first 72 hours of Fortnite’s release.

“Now is a really exciting time both for gamers and game developers,” said Tim Sweeney, Epic Games founder and CEO. “Right now we are 10 years into the mobile gaming revolution. This is a revolution that’s brought more than 3.5 billion new computing device owners into the market in the form of smartphones and tablets and billions of new gamers. So it’s one of the greatest events in the history of the game industry.”

To be clear, Sensor Tower’s numbers don’t reflect purchase data tied to Amazon payments or other shopping services available on iOS devices—they’re reportedly rooted in direct purchases from the App Store, only. However, the numbers do reflect revenue earned by free-to-play mobile games, which usually dangle in-app purchases in front of players. Additionally, lifestyle apps such as Tinder and Bumble reportedly saw a huge increase, with music apps seeing the smallest growth in 2017 at 8 percent.

Ultimately, with smartphones seemingly being in the pockets of people of all ages, and the hardware finally being able to support games hitherto reserved for the power of consoles or PCs, this increase in purchases makes sense. With the iPhone X being a popular smartphone option, and customers usually eager to test drive their new gadgets by purchasing the newest, most demanding software available, these numbers are rather logical. The interesting part will come around this time next year, when we’ll get to see just how stable or unstable this growth remained throughout 2018.