According to its recent most financial statement, the Mozilla Corporation, responsible for Firefox and Thunderbird development, makes 84 percent of its revenue from a search partnership with Google. All new installations of Firefox use Google as the default search engine, and most of Mozilla's revenue comes from that arrangement and similar deals with Microsoft and other search partners. The Google partnership was set to expire this November, but there's been no word from either Mozilla or Google as to whether it's been "reassessed."

In response to our questions about the future of a Google and Mozilla partnership, a Google spokesperson told us, "We generally don't disclose specific terms of business agreements. We can confirm that we still have an agreement with Mozilla, but have nothing new to share at this time." ZDNet's Ed Bott received a similarly vague response from Mozilla PR. 

A recent StatCounter report pegged Chrome as the world's second most popular browser, behind Internet Explorer at 40.63 percent, and placing Google's three-year-old browser ahead of Firefox. While StatCounter's numbers show an extremely slim margin of loss (and error) for Firefox, Chrome has gained significant marketshare in 2010 while Firefox stayed idle. Without an app ecosystem and amidst complaints of browser bloat, Firefox will need to do a lot more than offer apps like Firefox with Bing to stem the tide of users leaving for other browsers.

Update: Mozilla told All Things D's Liz Gannes that the Google relationship is in "active negotiation."

Our search relationship with Google remains positive for both of us. We are in active negotiations and have nothing further to announce at this time. We have every confidence that search partnerships will continue to be a strong and growing generator of revenue for the foreseeable future.