Win7 already claims 5.71% of Windows Version Installed Worldwide

In terms of OS versions, Windows saw the following changes between November and December: Windows XP dropped 1.28 percentage points (from 69.05 percent to 67.77 percent), Windows Vista dropped 0.68 percentage points (from 18.55 percent to 17.87 percent), and Windows 7 gained 1.71 percentage points (from 4.00 percent to 5.71 percent), meaning it has passed all versions of Mac OS. Speaking of which, Mac OS saw the following progress: version 10.4 dipped 0.04 percentage points (from 0.84 percent to 0.80 percent), version 10.5 dipped 0.14 percentage points (from 2.61 percent to 2.47 percent), and version 10.6 moved up 0.22 percentage points (from 1.38 percent to 1.60 percent). Taking the historical perspective, we can see that Windows Vista and Windows 7 together have just over a third of Windows XP's market share, while Mac OS 10.5 and 10.6 together have more than five times the market share of Mac OS 10.4.

Before the end of 2010, we're expecting to see Windows 7 pass Windows Vista, Windows XP to drop below the 50 percent mark, and Mac OS X 10.6 to pass 10.5 and 10.4 combined.