Powered by the increasing popularity of ringback tunes and mobile-based full-song downloads, digital-music sales in Japan rose 32% to 121.6 million units in the third quarter, according to new data released by the Recording Industry Assn. of Japan (RIAJ).

The wholesale value of digital download sales reached 20.1 billion yen ($184.2 million), up 47% from the July-September period of 2006, RIAJ says.

While mobile-based master-ringtone sales by the RIAJ's 47 member companies in the quarter were down 2% to 56.9 million units, for a value of 6.4 billion yen ($58.9 million), down 1%, ringback-tune sales rose 128% to 23 million units, for a value of 1.6 billion yen ($14.7 million), marking a 164% rise.

Sales of mobile-based full-track downloads, meanwhile, increased 112% to 30.3 million units, for a value of 9.4 billion yen ($85.9 million), up 103%.

Overall, mobile-based downloads rose 32% to 113.5 million units, for a value of 18.2 billion yen ($166 million), up 46%.

PC-based music downloads in the third quarter, meanwhile, were up 42% to 8.3 million units, for a value of 1.5 billion yen ($14.1 million), up 29%.

The RIAJ defines the PC-downloads category as comprising singles, albums, mini-albums and "other related content" sold over wired networks, with albums and mini-albums counting as single units regardless of the number of tracks they contain. The association says that although the data doesn't differentiate between sales of single tracks and albums, singles account for the overwhelming majority of download sales.

The mobile category comprises sales over wireless networks of full single tracks, ring tones, master ring tones and other related content.

Cumulative digital-download results for the first three quarters of 2007 show mobile-based music downloads rising 28% to 325.2 million units, for a value of 50 billion yen ($458.1 million), up 44%, while PC-based downloads in the January-September period rose 27% to 22.3 million units, for a value of 4.3 billion yen ($38.7 million), up 15%.

Total digital downloads, including miscellaneous categories, for the first three quarters totaled 347.5 million units, a rise of 28%, for a value of 55.3 billion yen ($506.8 million), up 44%.