Windows 7: Fastest-selling OS, 350 million licenses sold in 18 months

Microsoft has announced that Windows 7 has sold more than 350 million licenses so far, meaning it is still the fastest-selling operating system. Windows 7 has been available to the masses for 18 months. 
"We've done a lot in the last 18 months that improves upon the experience people have on their PCs with Windows 7," a Microsoft spokesperson said in a statement. "We launched Windows Live Wave 4 (which included Windows Live Essentials 2011 and enhancements to Hotmail), released the first service pack for Windows 7, and recently launched Internet Explorer 9. And we’re hard at work on further innovation for Windows.

At CES this year we announced the next version of Windows will support System on a Chip (SoC) and last week at MIX11 we released the first platform preview to developers for Internet Explorer 10." Windows 7 actually grabbed 20 percent of the market at the end of 2010. Between January and December 2010, Windows XP fell almost 10 percentage points to 56.72 percent market share, Windows Vista lost over five percentage points to 12.11 percent, and Windows 7 gained over 13 percentage points, pushing it to 20.87 percent.

In March 2011, Windows 7 had 24.17 percent of the market. By the end of this month, I would expect Windows 7 to pass the 25 percent market share mark, meaning one in four users would be using Microsoft's latest and greatest. Meanwhile, Windows Vista is on its way to falling below the 10 percent mark and Windows XP should soon drop below 50 percent.

Three months after release, Microsoft said more than 60 million Windows 7 licenses were sold. At the 15 month mark, the company had sold 300 million licenses. This means Microsoft was selling some 20 million licenses per month, although today's number means that sales have slowed down a tad.