iOS (formerly known as iPhone OS) is Apple's mobile operating system. Originally developed for the iPhone, it has since been extended to support other Apple, Inc. devices such as the iPod touch, iPad and Apple TV. Apple, Inc. does not license iOS for installation on third-party hardware. As of October 4, 2011, Apple, Inc.'s App Store contains more than 500,000 iOS applications, which have collectively been downloaded more than 18 billion times. In the last quarter of 2010, it had a 26% share of the smartphone operating system market in terms of units sold, behind Google's Android and Nokia's Symbian. As of May 2010, it accounted for 59% of mobile web consumption—including both the iPod touch and the iPad—in North America.