Has to be an old chart; Dr. Laura is on it.
Top radio show hosts of 2010. We're getting closer to today. I'm still looking for results from 2012.
Oops, forgot to link to the chart of top radio hosts for 2010.
http://www.stateofthemedia.org/files/2011/01/36-audio-top-talk-radio-hosts-2010.png