From the Fractions dept.:
The Linux kernel would cost more than one billion EUR (about 1.4 billion USD) to develop in European Union. This is the estimate made by researchers from University of Oviedo (Spain), whereby the value annually added to this product was about 100 million EUR between 2005 and 2007 and 225 million EUR in 2008. Estimated 2008 result is comparable to 4% and 12% of Microsoft's and Google's R&D expenses on whole company products.

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