You are looking at share... that is the percentage who are listening in any given moment. To evaluate, you have to look at cume, which is the circulation of AM stations and the band . AM radio cumes somewhere over 30% in just about every US market.Would love to see the math behind the 80 million listeners that David referenced. That would suggest one quarter of America regularly listens to AM radio. In the large and major markets I looked at, the number appears to be closer to 10 to 15 percent - and presumably declining with time.