The station also beats the station that carries Tony Snow and Sean Hannity.
I did find one clip that says in 2000 when KIRO carried the Mariner's, they had almost a 19 share in the evening when baseball is carried and lead most day parts. So obviously, the loss of baseball did hurt, but the liberal programming seemed to be pulling it's weight and was handily turning away popular conservatives.
Compare KIRO with where they used to be. In the mid 80s KIRO had the second highest local share of any AM station in the country. They averaged almost 10%. If they are 5th in the area now, they have fallen fast and hard.