Digital downloads account for 40% of US music sales

"U.S. album sales in 2009 declined for the eighth time in nine years, according to Nielsen SoundScan, while online song downloads grew too slowly to close the gap.
The data, released Wednesday, indicate that the recorded-music industry is still struggling to adapt to the digital age, even as SoundScan said digital downloads now account for 40% of music purchases.
Domestic album sales, including digital downloads, fell to 373.9 million units, a decline of 13% from 2008."
Source: Nielsen Soundscan, reported by the Wall Street Journal, 7th January 2010