Taylor Swift's '1989' Back at No.1 on Billboard 200

After a one-week vacation, Taylor Swift's stunning new album 1989 is back at number one of the Billboard 200 this week.

The Billboard 200, which has long been a chart that ranked the most popular albums of the week based on pure album sales, now shifts its methodology to a multi-metric consumption model. The ranking includes on-demand streaming and digital track sales, in addition to traditional album sales, all measured by Nielsen.

This is the most substantial update to the chart's methodology since May of 1991, when Billboard first used Nielsen's point-of-sale data — SoundScan — to measure album sales.

The new Billboard 200 chart uses accepted industry benchmarks for digital and streaming data, where 10 digital track sales from an album is equivalent to one album sale, and 1,500 song streams from an album equates to one album sale. All of the major on-demand audio subscription services are considered, including Spotify, Beats Music, Google Play and Xbox Music.

Swift's return to No. 1 is powered by 339,000 total album equivalent units in the week ending Nov. 30. Of that sum, the majority is pure album sales (281,000).

1989's album sales now stand at 2.5 million after five weeks on sale.