Today at Apple’s iPhone launch keynote, its CEO Tim Cook announced that the company has sold more than 7  million copies of Mountain Lion, more than doubling its tally since announcing 3 million downloads on July 30.

We already knew that the operating system was the most successful OS X release in Apple’s history, hitting the Mac App Store in in the last week of July. Last year, Apple announced it had served one million downloads of the previous iteration, OS X Lion, in 24 hours.

Mountain Lion is a $19.99 download from the Mac App Store and has not been offered as a physical release, expect if users requested a USB copy of the download.

When it launches, some users took advantage of a program that allows recently purchased Macs to grab a the update for free. That scheme didn’t go entirely to plan at first though, with some customers reporting ‘Code Has Been Used’ errors when trying to redeem their free download.

Apple soon rectified this by issuing new codes, which may or may not have been included in today’s figures.

A host of live blogs of today’s event including GDGT, The Verge, Engadget and Macworld are available.