Mozilla, the group behind the open source Firefox Web browser, has disclosed its 2006 revenue -- US$66,840,850. The figure marks a rise of 26 percent on the US$52.9 million that Mozilla made in 2005, with 2006 expenses slicing off only US$19.8 million.

"The highlight is that Mozilla remains financially healthy: we're able to hire more people, build more products, help other projects, and bring more possibilities for participation in the Internet to millions of people," Mozilla Foundation chairman Mitchell Baker said in a blog posting.

As in 2005, around 85 percent of the revenue came from Google, according to a related frequently asked questions page. Google is the default option in the Firefox search bar, and a Firefox-branded Google page is the default home page for Firefox.

However, the Google contract expires in November 2008, Mozilla said, at which point the foundation could extend the deal or look for other partners. "We have significant retained earnings, which allows us a good degree of flexibility," the foundation said on the FAQ.

The foundation funded the work of about 90 people by the end of 2006. "In 2007 we expect our expenses to be significantly higher as we have continued to hire and fund more people and develop additional programs," she said.