Sandvine published the Fall 2011 Global Internet Phenomena Report, with lots of details on real-time entertainment traffic.
"Within fixed networks in the United States, Real-Time Entertainment applications are the primary drivers of network capacity requirements, accounting for 60% of peak downstream traffic, up from 50% in 2010. Rate-adaptive video represents the majority of video bandwidth, with Netflix alone representing 32.7% of peak downstream traffic, a relative increase of more than 10% since spring"
Sandvine also created nice inforgraphic with the report. See it here - and the chart below showing the "fight" between Netflix and YouTube - how is bigger?
See "Sandvine’s Fall 2011 Global Internet Phenomena Report Indicates a Race for Services and Quality Delivery" - here and download the report from here.