Microsoft has sold 40 million Windows 8 licenses since Oct. 26 when the new operating system became available.

That includes all sales, corporate and consumer, although the company provided no breakdown for how many of each there were.

Thats up just about exactly tenfold from the first four days of the operating systems availability when CEO Steve Ballmer announced the figure at the companys developers conference.

 Ballmer said back in October that there are 670 million Windows 7 licenses that could be upgraded to Windows 8, plus the expected sale of 400 million new devices that he projects will be sold running Windows 8.

The sales numbers were issued by Tami Reller, corporate vice president and CFO of Windows, at the annual Credit Suisse technology conference Tuesday.

Reller also says the number of applications available for sale in the Windows Store has doubled since the Windows 8 launch from about 10,000 to about 20,000. Apps she highlighted among the new ones included CBS, ABC News, ABC Family, Engadget, Flixster, OWN (Oprah Winfrey Network), Vimeo none of which is a business productivity app.

See also:

Windows 8's early uptake trumps Vista's
Windows 8 apps store cracks 20,000, most of them free
Windows 8 interface called 'disappointing' by usability expert
Microsoft Windos 8 versus OS X Mountain Lion