In the two decades since Nielsen Soundscan started to keep track of U.S. album sales in 1991, the company has seen the industry fold in half, digital sales catch up to physical, and vinyl mount a resurgence. But until last week, they'd never seen old records outsell new ones.

With 150.5 million albums sold first half of the year, 76.6 million were catalog records (industry term for albums released more than 18 months ago), compared to 73.9 million current albums.

"That's a combination of two things: not having the big blockbuster new releases in the first half, and having very, very strong catalog," says Nielsen analyst David Bakula.

The top-selling catalog records of the year so far include Guns N' Roses' Greatest Hits and four records by Whitney Houston who died February. Bakula says the biggest reason catalog has been so strong is that record labels and retailers continue to drop the price of older albums, often to as low as $5.99 or $7.99. Those prices, sometimes half of what they once were, are bringing in new customers.

Old Records Are Outselling New Ones for the First Time - Orange County - Music - Heard Mentality