NEW YORK - Billboard is making a big change to the way it counts album sales by including streams of music from streaming music services like Spotify.

The magazine and Nielsen SoundScan will start adding streams and downloads of tracks to the formula behind the Billboard 200, the album charts seen as the music world's weekly scorecard, reported the New York Times.

It is Billboard's biggest change since 1991 in how it calculates sales, said the newspaper.

For the Top 200 album chart, they will count 1,500 streams from albums on services like Spotify, Beats Music, Rdio, Rhapsody and Google Play as equivalent to an album sale.

Ten downloads of individual tracks will also be calculated as one purchased album.

The Times said the new chart, covering sales and listening from Monday to Nov 30, will be revealed on Billboard's website on Dec 4 and published in print in its Dec 13 issue.