New data from App Annie shows China has overtaken the US as the world’s biggest source of iOS app store revenue.

Most of that revenue came from games – specifically collaborative mobile MMOs, which are apparently all the rage over there – but China’s exponential rise on iOS revenue will be as much a product of the rapidly increasing iOS installed base caused by Apple’s recent success over there.

MMO stands for massively multiplayer online, for those oblivious to the charms of World of Warcraft and the like. They originated on the PC but are well-suited to the freemium gaming dynamics of the most profitable mobile games as they typically lure the player into an immersive experience before then introducing paywalls in the way of further, or at least faster progress.

The most profitable game on iOS on iOS in China, according to App Annie, is Fantasy Westward Journey, a Chinese-made game that started life as a PC game 15 years ago. An MMO sub-genre that is also proving popular is the multiplayer online battle arena (MOBA) – typified by the massively popular PC game Dota 2. Tencent’s Hero Moba is apparently very similar to Dota 2 and is also very popular in China. Pokémon Go, of course, has also done well and apart from games video streaming and social media are heading in the right direction.