Despite Android being widely used by smartphone makers, Google has struggled to gain traction for app sales in Android Market. Apple's iOS platform continues to eat up around 90 percent of mobile software revenues.
Google previously described a $1 billion run rate for mobile revenues in just 2011, which includes both mobile ad revenue and Google's 30 percent cut on paid Android app sales through Google Play (formerly Android Market).
While Google's chief executive Larry Page recently described an $2.5 billion annual run rate for the company's mobile revenues, the company has testified that it has earned less than $550 million from Android across four years from 2008 to 2011.
Google doesn't publicize its Android revenues, but has called out the the growing minority of its revenues attributed to mobile devices. Compared to the $2.5 billion it expected to earn on mobile devices this year, Google reported $38 billion in total revenues for 2011, most of which comes from paid search results presented to desktop PC users.
The last four years of Android revenue amounted to less than $550 million, the company's documents stated, according to a report by The Guardian. Spread across four years, that indicates that Android contributes very little toward Google's mobile revenues.