Mozilla has just released Firefox 4, and in less than a day clocked more than twice the downloads Microsoft boasted about after the release of Internet Explorer 9.

Now website analytics company StatCounter says Mozilla’s new browser has already taken 1.95 percent of the worldwide Internet browser market.

In contrast, StatCounter adds, Internet Explorer 9 has taken only 0.87 percent of the worldwide browser market a week after its debut.

And as you can tell from the screenshot above, not only Firefox 4 but also the recently released Opera 11 browser has a steady lead over IE9 at this point.

Worth noting: Internet Explorer 9 isn’t compatible with Windows XP, ageing operating system that was released ten years ago but still has an enormous user base around the world.

When all versions of each browser are taken into account, IE still leads the global market with 45 percent, followed by Firefox with 30 percent and Chrome with 17 percent, StatCounter says. The web analytics company recently reported that Firefox overtook IE to become the number one browser in Europe for the first time in December 2010.

In the US, IE (all versions combined) leads the market with an even bigger margin: 48 percent, followed by Firefox at 26 percent and Chrome at 14 percent.

StatCounter says its Global Stats numbers are based on aggregate data collected on a sample exceeding 15 billion page views per month from a network of more than three million websites.