Google's Android software for mobile devices was running on 75 percent of smartphones shipped in the third quarter, according to research firm IDC. According to the IDC, total Android smartphone shipments worldwide reached 136.0 million units, accounting for 75.0% of the 181.1 million smartphones shipped in 3Q12. The 91.5% year-over-year growth was nearly double the overall market growth rate of 46.4%.

"Android has been one of the primary growth engines of the smartphone market since it was launched in 2008," said Ramon Llamas, research manager, Mobile Phones at IDC. "In every year since then, Android has effectively outpaced the market and taken market share from the competition. In addition, the combination of smartphone vendors, mobile operators, and end-users who have embraced Android has driven shipment volumes higher. Even today, more vendors are introducing their first Android-powered smartphones to market."

"The share decline of smartphone operating systems not named iOS since Android's introduction isn't a coincidence," said Kevin Restivo, senior research analyst with IDC's Worldwide Quarterly Mobile Phone Tracker. "The smartphone operating system isn't an isolated product, it's a crucial part of a larger technology ecosystem. Google has a thriving, multi-faceted product portfolio. Many of its competitors, with weaker tie-ins to the mobile OS, do not. This factor and others have led to loss of share for competitors with few exceptions."

Android, having topped the 100 million unit mark last quarter, reached a new record level in a single quarter. By comparison, Android's total volumes for the quarter were greater than the total number of smartphones shipped in 2007, the year that Android was officially announced. Samsung once again led all vendors in this space, but saw its market share decline as numerous smaller vendors increased their production, IDC found.

iOS was a distant second place to Android, but was the only other mobile operating system to amass double-digit market share for the quarter. The late quarter launch of the iPhone 5 and lower prices on older models prevented total shipment volumes from slipping to 3Q11 levels. But without a splashy new OS-driven feature like Siri in 2011 and FaceTime in 2010, the iPhone 5 relied on its larger, but not wider, screen and LTE connectivity to drive growth.

BlackBerry's market share continued to sink, falling to just over 4% by the end of the quarter. With the launch of BlackBerry 10 yet to come in 2013, BlackBerry will continue to rely on its aging BlackBerry 7 platform, and equally aging device line-up. Still, demand for BlackBerry and its wildly popular BBM service is strong within multiple key markets worldwide, and the number of subscribers continues to increase.

Symbian posted the largest year-on-year decline of the leading operating systems. Nokia remains the largest vendor still supporting Symbian, along with Japanese vendors Fujitsu, Sharp, and Sony. Each of these vendors is in the midst of transitioning to other operating systems and IDC believes that they will cease shipping Symbian-powered smartphones in 2013. At the same time, the installed base of Symbian users will continue well after the last Symbian smartphone ships.

Windows Phone marked its second anniversary with a total of just 3.6 million units shipped worldwide, fewer than the total number of Symbian units shipped. Even with the backing of multiple smartphone market leaders, Windows Phone has yet to make a significant dent into Android's and iOS's collective market share. That could change in 4Q12, when multiple Windows Phone 8 smartphones will reach the market.

Linux volume declined for the third straight quarter as did its year-over-year growth. Samsung accounted for the majority of shipments once again, but like most other vendors competing with Linux-powered smartphones, most of its attention went towards Android instead. Still, that has not deterred other vendors from experimenting, or at least considering the open-source operating system, as multiple reports of Firefox, Sailfish, and Tizen plan to release new Linux-based experiences in the future.

Here are IDC's top operating systems based on worldwide smartphone unit sales and market share in the third quarter of 2012.

- Android (Google) - 136 million units, 75 percent share (57.5 percent a year earlier)

- iOS (Apple's iPhone) - 26.9 million units, 14.9 percent share (13.8 percent a year earlier)

- BlackBerry (Research in Motion) - 7.7 million units, 4.3 percent share (9.5 percent a year earlier)

- Symbian (mostly used by Nokia) - 4.1 million units, 2.3 percent share (14.6 percent a year earlier)

- Windows (Microsoft) - 3.6 million units, 2 percent share (1.2 percent a year earlier)

- Linux - 2.8 million units, 1.5 percent share (3.3 percent a year earlier)