Sensor Tower, a site that tracks app growth, has announced that as of the end of January, Pokémon GO has brought in over $1 billion in revenue. This makes it the fastest growing mobile game (in terms of revenue) in the history of mobile games, as the game only launched in July of last year, a little less than seven months ago. Not bad for a game that’s free to play, with in-app purchases that are completely optional and not really necessary to get anything more out of the game. By comparison, another popular mobile game, Clash Royale, brought in about $550 million in its first seven months and is currently almost at the $1 billion mark itself, having launched eleven months ago in March of last year.

As of September, Pokémon GO had been downloaded an estimated 500 million times, according to Expanded Dramblings. That means that many more people are playing Pokémon GO than are playing the new main series games Pokémon Sun and Pokémon Moon, which sold a combined total of about 14.7 million units since their releases in November. Also reported by Nintendo was another mobile game, Super Mario Run, having been downloaded over 40 million times in just its first four days. No wonder Nintendo has decided to release at least two mobile games a year from here on out.

Sensor Tower also disclosed that when Pokémon GO first came out, it was making about $18 million a day, as opposed to the $1.5 million to $2.5 million a day it has been making as of late. It’s normal for a game’s popularity to reach it’s height when it first comes out, before players have gotten a chance to play it so much that they eventually get bored of it. However, Niantic, the company behind the game, has been teasing the inclusion of Johto Pokémon for months now, so when they finally get included in the game, Pokémon GO may see something of a resurgence.