What a great question, I was looking for this data for a presentation at gave at FOWA 2010 last week. See slide 30 http://www.slideshare.net/davidhauser/fowa-2

What a great question, I was looking for this data for a presentation at gave at FOWA 2010 last week. See slide 30 http://www.slideshare.net/davidhauser/fowa-2010 http://www.slideshare.net/davidhauser/fowa-2010