Browser usage numbers for 2006 are beginning to appear on the Web, and for the first time in many moons the market share of Microsoft’s dominant offering, Internet Explorer, has dipped below 80 percent. While Internet Explorer’s star was sinking, its chief competitor’s, Mozilla Firefox, was ascending. Its market share climbed from 9.50 percent in January 2006 to 14 percent in December — just about the time version 2.0 of the browser was released.

Source: Firefox 2.0: Subtle Changes, Big Difference