Despite launching only two years ago, Google's Chrome now represents 9.98% of the total browser market share according to that Windows 7 gained more than 13% during 2010, closing the year out with 20.87% of the operating system market. That's one in five computers, mind you. Windows XP is slowly losing footing, falling some 10% to 56.72% during the year. Meanwhile, Vista dropped more than 5% to 12.11%. Mac OS X 10.6 and 10.5 collectively represent 4.51% (1.45 and 3.05%) as of December.