Tarmo Virki, European Technology Correspondent

Worldwide mobile application store revenue will almost triple to $15.1 billion this year, boosted by a surge in Google's Android market, research firm Gartner said on Wednesday.

Apple created the market for mobile online software stores with the iPhone store in mid-2008, scoring an instant hit that drove smartphone sales and reshaped the way mobile content is delivered.

We estimate that Apple's App Store drove close to nine application downloads out of 10 in 2010 and will remain the single best-selling store ... through 2014, although to a lesser extent, as other stores manage to gain momentum, analyst Carolina Milanesi said.

Last week, Apple's App Store reached 10 billion downloads. Its closest rivals are Google's Android and privately held GetJar which sells software for all platforms and reached 1 billion downloads last June.

Android, offered free to cellphone vendors, was expected to become the world's most popular smartphone operating system this year as vendors like HTC, Motorola Mobility and Samsung Electronics roll out new models.

Gartner forecast 81 percent of all downloads this year will be made for free.

It said 16 percent of application store markets' $5.2 billion revenue was generated from advertising, a share it expected to nearly double to 30 percent by the end of 2014.

(Editing by Dan Lalor)

App