Europemedia.net says half of online radio is from outside the US:
In the last year alone the number of radio webcasters has declined by thirty one per cent, with US stations accounting for the majority of this steep decline. Based on the high copyright fees supported by the RIAA, well over one thousand US stations and internet-only webcasters quit streaming online.
The current number of webcasting channels on the net is 3940, significantly lower than the all time high of 5710 stations from last year. Prior to this year US based stations represented nearly 60 per cent of all stations webcasting. Now international stations account for well over 50 per cent of all stations webcasting online.