The Mozilla Foundation has posted a 21 per cent rise in revenues over 2006, increasing its earnings to $66.8m.

Earnings before interest, tax. depreciation, and amortization (Ebitda) reached 47m, up 5.2 per cent from last year.

The Mozilla foundation oversees development of the open source Firefox browser as well as projects such as the Thunderbird email client and the Seamonkey internet suite.

Mozilla makes most of its money from a partnership with Google. The search giant is the default search engine in Fifefox's built-in search function. Mozilla last year received $61.5m from search royalties, the majority of which comes from Google.

Mozilla nearly doubled its programming expenses, which go mostly to paying the salaries of 90 developers who work for the group. The foundation's headcount outgrew revenues. In a blog posting, the foundation's Mitchell Baker projected a continuing hiring spree.

Hosting costs for Mozilla's websites were the second highest cost items. The group last year served up 600,000 daily Firefox downloads and 25 million daily update requests.