Old records are outselling new ones for the first time ever since Nielsen Soundscan started tracking album sales back in 1991. According to OC Weekly, 76.6 million catalog records--these are the "old," or 18 months or older releases--were sold in 2012's first half compared to the sales of 73.9 million new albums.
Nielsen analyst David Bakula attributes this phenomenon to two things: "not having the big blockbuster new releases in the first half, and having very, very strong catalog." Those catalog releases he's referring to include Guns N' Roses' Greatest Hits and four Whitney Houston records, the latter of which saw skyrocketing sales following her death this past February. Another factor is the fact that catalog releases are typically priced $7.99 to to $10.99 while new releases usually range from $13 to $18.