According to a report by the research firm Yankee Group, only one in five digital music sales in the U.S. happens over a mobile device.

Michael Goodman, director of Yankee Group’s digital entertainment practice, reportedly told a group at CES that despite carriers’ continued efforts, online distribution accounts for 80% of revenue for the music industry.  The research group also reported that though there are more than 266 million mobile music phones now in use, only 9% of mobile users actively use them as portable music players.

As for business models that might help with customer uptake of mobile music, Goodman cited Nokia’s new service Comes With Music, which offers users of select handsets a year’s worth of unlimited access to mobile music downloads for free.