If any confirmation was needed for the popularity of digital music, it was reached yesterday when Apple's popular iTunes music store reached a 5 billion song milestone. That adds up to $4.95 billion in digital revenues over a five year period.

That said, people are still buying CDs. According to shipment statistics from the recording industry, CD sales alone over the same period amounted to nearly $49 billion with $7.4 billion coming in 2007 alone. As iTunes represents 70% of the legal download market, this means digital still only represents about 15% of music sales overall. (Yes, we looked it up)

Have you made the shift to digital yet? Are you planning to?