Those are Arbitron numbers, and anyone can take them and shape them any way they want.
When "the book" comes out, you'll hear every radio station in town declare "WE'RE #1!" And they will all be correct. It just depends on how you read the numbers.
My question really is the 20 million that is tossed about by Rush and his followers. This isn't unique listeners is it? In other words he may have 20 million in a week but if someone listens 5 days a week then he is counted five times..... so if he has a bunch of daily repeat listeners then in effect they are counted several times is that correct.