• by Gavin O'Malley  @mp_gavin, February 15, 2016

Across all app stores, the global mobile app market will grow by 24% to reach $51 billion in gross revenue this year, according to a fresh forecast from App Annie.

For the first time since the dawn of apps, however, the United States will not be leading the way. China will surpass the U.S. in terms of total revenue from app stores by the first half of this year. The Asian tiger already surpassed the U.S. in downloads, early last year.

By 2020, gross global revenue across all app stores will exceed $101 billion, the research firm predicts.

More broadly, mature markets will see continued growth while emerging markets like India, Indonesia, Brazil, Argentina and Turkey are expected to expand the most dramatically through 2020.

“The combination of steady growth in many mature markets along with rapid growth in emerging markets will propel the market’s continued expansion,” Danielle Levitas, SVP of research & analysis at App Annie, notes in a new report.

“While large markets including the United States, Japan and China are central to overall app revenue growth, we see tremendous opportunity in fast-growing markets from India and Indonesia to Mexico and Argentina,” according to Levitas.

In terms of app downloads, Google’s Android increased its lead over Apple’s iOS in 2015, while Apple continued to generate a disproportionate share of revenue.

In fact, Google Play saw 100% more downloads than Apple’s App Store, in 2015, according to recent findings from App Annie. That was up from the 60% lead that Google had over Apple, in 2014.

The growing lead seemingly marked the beginning of major changes in mobile marketing, including substantial increases of Android’s share of mobile ad spend, the research firm suggests.

App Annie credited Google’s gains to huge demand from first-time device owners in emerging markets including Brazil, India, Indonesia, Turkey and Mexico.

That said, iOS still managed to generate about 75% more revenue than Android in 2015. These gains were driven by strong growth driven by China, the United States and Japan, which contributed nearly 90% of the iOS App Store’s year-on-year revenue growth.