27 songs sold more than 100K units during the post-Christmas rush in the US, with 10 exceeding 200K. In 2006, only 15 songs sold more than 100K and 4 sold more than 200K – according to Nielsen SoundScan. Not a single track sold more than 500,000 digital units in 2004, but 114 did in 2007, and 61 tracks in 2006. Meanwhile, 36 tracks passed the 1 mln sales mark, more than double the 17 in 2006.