A report claims that there are just 25 developers taking half of the revenue made by Apple's App Store and Google Play in the US.

Canalys claims that during a 20 day period in November, 25 developers took more than half of the $120m in total revenue generated from paid app downloads and in-app purchases, reports Tech Crunch.

Those developers include Disney; Electronic Arts; Gameloft - The Dark Knight Rises, My Little Pony Friendship is Magic; Glu; Kabam; Rovio - of Angry Birds fame; Storm8 - Racing Live, iMobsters, and Zynga - FarmVille.

The report notes that 145 of the top 300 apps in the Apple App Store were games the one exception being the Pandora music streaming app.

These top-selling game makers tend to dominate the charts because they offer multiple products, such as different versions of Angry Birds.

In related news, app developers are apparently showing no interest in developing for the Microsoft Surface, with the "most glaring omission" being Facebook, according to a report on AdAge.

According to ComScore, Pandora and Twitter receive 81.1% and 53.6% of their US traffic from mobile devices, yet, neither company has an app available for the Surface, writes AdAge.

Developers appear to be reluctant to build apps for Surface in spite of Microsoft offering revenue splits that are "more favourable" than those offered by Apple and Google, notes the report. According to AdAge, Microsoft offers the same 70-30 split until a company earns $25,000 in revenue from the Windows app store. After that, developers get to keep 80% of app revenue.

App analytics firm App Annie notes that only Gameloft has at least one app available for the Surface.

The report notes that Surface didn't launch until September, which "isn't a lot of time to build a complicated app", according to Ray Velez, chief technology officer of digital agency Razorfish.

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