Fortnite, the free-to-play game that has captivated gamers and non-gamers alike since it launched in 2017, made a record $318 million in revenue in May, beating out every game on any platform in the history of gaming.

How is that possible if it's "free to play"? The term means users don't need to make any purchases to get the gaming experience, but games like Fortnite do offer in-game purchases like outfits, characters, tools, and even dance moves so creators can make a profit off of players. As this chart from Statista shows, it's a business model that's working for developers like Fortnite creator Epic Games.

Fortnite made Epic Games about $95 million more in a month than the next leading free-to-play game did for its creator back in July 2017. It's made a total of $1.2 billion in revenue since it launched, according to SuperData Research cited by Recode.

The chart also reinforces the idea that the gaming market is on its way up; the months with the highest grossing games are all within the last two and a half years, with Clash of Clans (February 2016) being the oldest.