Google is expected to launch their music service this afternoon, so we decided to look at some of Google’s history with the Music category. Of course we all know that the majority of people start with Google for search – last month, 71% of all searches took place on Google. Out of the top 1000 search terms that took place on Google last week, 6% were music-related (includes bands, music services and content). Last week, Google sent 1.48% of their total visits to the Music category and of those visits, 95% of the downstream traffic to Music websites were returning visitors (that had visited Google in the past 30 days).

Google was the top referral website to the Music category accounting for nearly 30% of the total traffic to the category last week, 5x more than 2nd ranked Yahoo! Search and 6.3x more than MySpace.

Last week, 15% of the clicks from the search term portfolio of Music that includes the names of over 900 band & artist names resulted in a visit to a Google property, especially YouTube, among the Top 10 websites to receive traffic.

Now we can just wait and see what Google Music will look like and what overall impact the service will have on the category.