Analyst firm Canalys estimated that 25 developers accounted for 50 percent of app revenue in the U.S. Apple App Store and Google Play during the first 20 days of November 2012.

Based on the firm’s daily App Interrogator surveys, the 25 developers generated $60 million in revenue from premium downloads and in-app purchases over this period. Despite the combined number of apps in the App Store and Google Play at around 1,400,000, 24 of the 25 top grossing developers are game developers, with music streaming provider Pandora as the lone non-game developer. The list of game developers include Zynga, Electronic Arts, Disney, Kabam, Rovio, Glu, Gameloft and Storm8′s Team Lava.

Looking past just the top 25, games accounted for 145 on average of the top 300 paid apps in the App Store and 116 of the top 300 paid apps on Google Play. Games not only dominated the top paid apps, they also took a huge chunk of the top free apps, with 94 of the top 300 for Apple and 110 for Google Play.

Canalys senior analyst Tim Shepherd said in a statement that discoverability is an issue in the app stores for developers of other types of apps, especially ones without a lot of brand recognition. He added that game developers are already prevalent in the app stores, so non-game developers need to figure out ways to promote their app such as social media and social recommendations, tactical games promotions and discounts, branding tie-ups and targeted in-app advertising.

Now that the holidays are in full swing, Canalys expects to see a majority of the top game developers pushing out discounts and special offers to take advantage of their ability to cross-promote within their app offerings, says vice president and principal analyst Chris Jones. He expects game developers’ dominance in the app stores to only increase through Christmas in the U.S.