In terms of actual numbers; digital albums sold nearly 120 million units, and digital tracks were at 1.34 billion units. Also noteworthy is that while CD sales decreases by more than 10%, music sales in general are up more than 3% overall. This comes after a decade of declining sales. The "Alternative" category - which includes punk and indie rock - is the most popular non-rock category in digital, but genres like country and R&B are catching up quickly.
Check out the full report here.