Mozilla last week declined to say whether it has renewed its contract with Google, a major revenue stream that keeps its Firefox browser in business.

If it fails to reach a new agreement with Google, Mozilla could see its revenues plunge by 80% or more.

The contract between Mozilla and Google was set to expire in November.

When asked if it had negotiated a new contract with Google, Mozilla declined to answer. Instead, it issued a statement that it has used before.

"We currently have partnerships with a number of search providers that differ by market, including major search partners including Google, Bing, Yahoo, Yandex, Amazon, eBay and others," a Mozilla spokeswoman said in an email. "We have every confidence that search partnerships will remain a solid generator of revenue for Mozilla for the foreseeable future."

That statement was virtually identical to one Mozilla has used in previous years when asked about its relationship with Google, most recently in an October FAQ that accompanied its annual financial report.

In the 2010 report, Mozilla did not disclose the amounts it received from individual search partners, but said that payments from search services accounted for 98% of the year's revenues, or $121.1 million out of a total of $123.2 million.

Mozilla receives revenues from search engines when Firefox users click on ads placed on search results pages.

Firefox, which has long set Google as Firefox's default search engine, has relied on the rival for most of its income. In 2008, the last time Mozilla broke out payments by search partner, it said Google accounted for 88% of its royalty revenues.

Although a note in the 2010 financial report didn't name Google, Mozilla said there that a search contract "which expires in November 2011" had provided 84% of its 2010 income, and 86% of its 2009 revenues.

If the Google contract had not been in place in 2010, Mozilla's revenues would have been just $19.7 million.

Questions about Mozilla's dependence on Google have been raised since the latter launched its own Web browser, Chrome, in September 2008. According to Internet metrics firms StatCounter and Net Applications, Chrome owned a 25.7% or 18.2%, respectively, of the global browser usage share in November, compared to Firefox's 25.2% or 22.1%.

StatCounter's numbers indicated Chrome had already passed Firefox to take second place behind Microsoft's Internet Explorer (IE), while Net Applications' hinted at a takeover by Chrome as soon as April or May 2012.

As of Sunday, new installations of Firefox continued to use Google as its default search engine.

Mozilla has, however, taken small steps to wean itself from Google, including a customized edition dubbed "Firefox with Bing," which uses Microsoft's Bing search as the default engine in both the browser's search box and its "Awesome Bar," the dual-use address bar where users can also enter search queries.

In 2007, Mitchell Baker, then Mozilla's CEO -- now the chairwoman of the Mozilla Foundation, the non-profit group that oversees Mozilla Corp., the entity actually responsible for Firefox development -- said that Mozilla could live without Google's money if necessary.

According to its 2010 financial statement, Mozilla had approximately $105 million bankrolled in money market accounts, government and commercial bonds, and other securities.

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, or subscribe to Gregg's RSS feed . His e-mail address is gkeizer@ix.netcom.com.