Sales of digital singles soared to 366.9 million units last year--up 163 percent from 2004's 139.4 million, according to new statistics from the Recording Industry Association of America. Full-length
digital album shipments grew 198.5 percent, from 4.6 million units to 13.6 million. The RIAA also reported that the music industry last year shipped 170 million ringtones, ringbacks, and other mobile
content, representing $421.6 million in retail value.