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

The growing lead could mark 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.

The research firm also found that in-app purchases (IAPs) as a share of app store revenue continued to grow in 2015 as subscription revenue made incredible gains.

Annual downloads on Google Play surpassed those on the iOS App Store for the first time, stateside.

In the U.S., Google Play’s share of combined iOS and Google Play downloads grew from about 45% in 2014 to 55% in 2015. Game downloads drove a significant portion of this shift with Google Play game downloads at one-and-a-half times iOS game downloads in 2015 -- up from nearly equivalent values the year before.

The strongest app categories included those that specialize in video, music, dating, and gaming.

Growth in iOS revenue helped drive monetization for new categories of the app economy, proving to an increasing number of businesses that mobile and apps are a viable and vital route for profitable growth.

Going forward, App Annie believes that there is still significant room for growth in the mobile app economy. That’s because device penetration remains relatively low in a number of emerging markets, and future increases are likely to bolster download growth.

Store revenue will continue to grow as audiences broaden and monetization options such as in-app subscriptions gain further traction in the coming year, the firm forecasts.