You’d think everyone who wants to listen to Queen’s Greatest Hits already owns a copy of the album. But here, you’d be wrong.

As of two weeks ago, old albums outsold new ones for the first time since Nielsen Soundscan started tracking U.S. album sales, back in 1991. The first half of 2012 brought sales of 76.6 million catalog albums (i.e, albums released more than 18 months ago) as opposed 73.9 million current albums. Some of the best-selling catalog albums are fairly recent beasts that won’t go away (Adele’s 19, Taylor Swift’s Speak Now); some are ancient classics that should be carved into Mount Rushmore (Dark Side Of The Moon, Licensed To Ill).

According to Nielsen analyst David Bakula, the primary catalyst for the trend is cost: Catalog albums are usually priced between $5.99 and $10.99, while new albums are often $13-$18. “I really, truly do believe that there probably is a consumer that is buying music here that wasn’t buying music in the past,” Bakula told the OC Weekly.

But surely there are other reasons, things that depress the sales of new albums more than they inflate the appeal of old albums — including everything from streaming services to the effects of the Long Tail to the overlap in demographics between file-sharers and fans of new music. Right? Plus, y’know, the fact that there’s a longstanding bias (masked as “traditional wisdom”) suggesting old music is simply better than new music.

So what is it? Do you buy new albums? Old albums? Would you buy more new albums if they cost less? Is cost even a factor? Are you buying any music at all, old or new, or what?