Spotify Foe Swift at Number 1 on US Streaming-Backed Chart

Swift's 1989 - which last month had the biggest debut of any US album in 12 years - returned to the top spot on the Billboard 200 for the seven days through Sunday after slipping for one week.

As part of the chart's biggest revamp since 1991, tracking company Nielsen SoundScan is including streaming in its measurements amid the rapid growth of services such as Spotify which allow music fans to listen to unlimited music on demand.

Swift benefited from another change as part of the Billboard 200's revamp - digital downloads of songs, with 10 purchases equivalent to one album sale. She sold 339,000 'album equivalent units' in the week, with 83 percent of the sales still traditional album sales either in physical or digital format.

1989 also gained ground due to the lack of a new blockbuster debut. British boy band One Direction's Four, which dethroned Swift when it came out, slipped in its second week to, incidentally, number four.

New release Shady XV, a compilation double-album by Eminem and affiliated rappers, entered at number three. Number two was a Christmas album by the Texas a cappella group Pentatonix.

The clearest beneficiary of the chart's changes was teenage star turned pop singer Ariana Grande, whose My Everything shot up from number 39 to number seven, with one-third of equivalent album sales made up of track sales or streaming.

Under the new formula, an artist registers one album sale for every 1,500 streams of songs from that single work.

Swift caused a stir by pulling her whole catalog last month off Spotify, accusing the Swedish company of devaluing music by insufficiently compensating artists. Swift's work minus 1989 remains on rival services such as Google Play, Apple-owed Beats Music and Rhapsody which require payment.

Emerging artists on Spotify
Spotify rejected Swift's charges and said that its 50 million listeners offered a rare source of growth for the beleaguered music industry.

The streaming service released its own type of chart on Wednesday. It said that British singer Ed Sheeran was Spotify's most streamed artist in 2014, with more than 840 million listens so far this year.

Pharrell Williams' viral anthem Happy was the most streamed single song, played more than 260 million times.

The Irish singer Hozier was identified as having the most viral track with Take Me to Church. With the popularity of the song, Hozier's debut album opened in October at number two on the Billboard 200, which then did not consider streaming.

"Spotify was a big part of getting the music across the world as quickly as it did, and as a new artist ... that's invaluable," Hozier said in a video released by Spotify.

Spotify also shed light on the most popular tracks by country. The German house DJ Robin Schulz was dominant in Europe, topping playlists in Britain, France, Germany, Ireland and Sweden.

The US pop rockers Maroon 5 enjoyed a strong following in Asian regions where Spotify is present, ranking number one or two in Hong Kong, Malaysia, the Philippines, Singapore and Taiwan.

Australian hip hop artist Iggy Azalea's Fancy was number one in both the United States and Australia and number two in New Zealand after Sam Smith's Stay With Me.