What is the economic value of open source software? A report by Linux Foundation

The Linux Foundation has carried out a quantitative study to try to determine the economic value of open source software. The result is that the value of all projects managed by the foundation can be estimated at 5 billion dollars.
Here is the summary table and the complete report entitling A $5 Billion Value: Estimating the Total Development Cost of Linux Foundation’s Collaborative Projects (realized by Jeff Licquia and Amanda McPherson).