Bridge Ratings has released its latest survey results on the world of digital music and satellite radio. According to their study, the amount of songs on a person's portable MP3 player varies by the amount of weekly radio listening done. Those who are below-average listeners to radio have more songs on their MP3 players.

The average radio listener (combining terrestrial, satellite and Internet radio) spends 34 hours per week tuned in. The average MP3 player owner has 349 songs on their device. Light radio users have an average of 410 songs while heavier radio listeners have an average of 289.

Also notable from this study was that 67 percent of radio listeners ages 12+ said they are not interested in being able to listen to music on their cell phones. Among 12-17 year-olds, just 26 percent said they were interested in MP3-capable cell phones.

As part of Bridge Ratings' ongoing study of satellite radio, the company asked satcaster subscribers about their plans to re-up with XM or Sirius. Among those who initially signed on via retail, 78 percent planned to renew their subscriptions. However, among those who signed up through a new car deal or Original Equipment Manufacturer (OEM), 54 percent planned to renew.

Bridge's latest projections show XM ending the year with 8.1 million subscribers and Sirius with 6.5 million.