The latest data on browser market share indicates that Mozilla's Firefox has broken the 20 per cent barrier in worldwide adoption.

Figures collected by Net Applications show that Firefox's November market share was 20.78 per cent.

Microsoft's Internet Explorer fell below 70 per cent for the first time, while Apple's Safari browser was used by over seven per cent and Google's Chrome by fewer than one per cent.

"Reaching 20 per cent worldwide market share is a significant milestone for Firefox and Mozilla," said Mozilla chief executive John Lilly.

"It is a huge achievement by the global Mozilla community that most would have considered impossible just a few years ago.

"The open web is more vibrant than ever, and the thousands of Mozilla contributors around the world have played a major role in making it that way."

Net Applications suggested that Firefox gained market share owing to a number of factors. Since it is used primarily in the home, rather than in corporate environments, the Thanksgiving holiday season will have helped its use.

Higher unemployment may also be helping Firefox, since more people are browsing from home rather than from the office.