Analyst firm Gartner has published its latest forecasts for the mobile apps industry, claiming that the number of downloads will top 45.6bn this year, up from 24.9bn in 2011. The company thinks that 89% of them will be free, while 90% of the 5bn paid downloads will cost less than $3. Gartner estimates that Apple’s iOS platform will account for more than 21bn app downloads in 2012, up 74% year-on-year. However, it sees Android’s Google Play and Windows Phone’s Marketplace as significant players going forward, as well as Amazon’s Appstore, Facebook’s App Center and – in China – a host of independent Android app stores. Finally, Gartner sees in-app purchases continuing to grow, from 10% of app revenues in 2011 to 41% in 2016.