Google’s Android is expected to overtake Apple’s iOS as the mobile operating system of choice by 2012, according to market watchers iSuppli.

The firm claims that Android will be used in 75 million smart phones by 2012, up from 5 million in 2009. Usage of iOS will rise to 62 million in 2012, up from 25 million in 2009.

In terms of market share this will give Android 19.4% in 2012, up from just 2.7% in 2009, while Apple will be on 15.9% in 2012 compared to 13.8% in 2009. In 2014, Android’s share of global smartphone OS usage will rise to 22.8%, while iOS will decline to 15.3%, iSuppli said.

"Android is taking the smart phone market by storm," said Tina Teng, senior analyst, wireless communications, for iSuppli. "The OS started with entry level models in 2008, but the flexibility Android offers for hardware designs and its appealing business model in terms of revenue sharing have attracted vigorous support from all nodes in the value chain, including makers of high-end smart phone models."

Adoption of Android will of course be boosted by the fact that it is available across a wide variety of handsets compared to Apple’s iOS, which is available just on the iPhone. However iSuppli claims that the proprietary nature of the iOS and Apple’s closed system business model will limit the number of smartphones with the operating system.

The mobile market represents the most lucrative growth opportunity in the technology world at the moment, according to iSuppli. It estimates that global carrier revenue for wireless data services, excluding messaging but including data access fees, will grow to approximately $250bn by 2014, up from $108.6bn in 2009.