Apple has announced the 15 billionth download from the App Store.

Having launched in July 2008, the App Store reached the 10 billion milestone in January this year, meaning the last five billion apps have been downloaded over the course of the last sixth months.

"In just three years, the revolutionary App Store has grown to become the most exciting and successful software marketplace the world has ever seen," said Philip Schiller, Apple's senior vice president of Worldwide Product Marketing. "Thank you to all of our amazing developers who have filled it with over 425,000 of the coolest apps and to our over 200 million iOS users for surpassing 15 billion downloads."

According to Apple there are more than 425,000 apps in the App Store. As Macworld recently reported, 100,000 of these are native iPad apps.

The App Store has proved lucrative for developers too, with a recent study showing that it's more common for apps in the iOS App Store to make money than it is for apps in the Google Android Market.

The success of the App Store led Apple to try the formula for Mac OS X, with the Mac App Store launching in January of this year. It has also brought imitators. Apple is currently taking Amazon through the courts over the latter's use of the term 'Appstore'.

The App Store has also had its fair share of controversy too, most recently over the introduction of subscription-based apps earlier this year. There has also been criticism of Apple's seemingly arbitrary decisions to block some apps, whereas some distasteful and offensive ones have managed to slip through the net.

However, with apps posing by far the greatest security threat to mobile devices, Apple's strict App Store policies have done a good job of protecting iPhone, iPod touch and iPad users.