For one thing you have to define, What Is Urban. Urban has taken on a different meaning from 30 years ago, just like the Adult Contemporary format today is not the same AC back in the 1970s and 80s.
WBLS, (98.7 Kiss-FM) WRKS, (Power 105.1) WWPR-FM and (Hot 97) WQHT which of the four are true urban stations? Kiss-FM and WBLS are very much adult leaning and Power 105.1 and Hot 97 both play a heavy rotation of Rap or Hip-Hop more than BLS and WRKS played 25 years ago.
Thanks,
kevin L. Sealy