Bruno Mars’ “Locked Out Of Heaven” spends a fourth week at No. 1 on the Billboard 100, but look for Taylor Swift possibly to end his tenure next week.

“Locked” remains No. 1 on Billboard’s Radio Songs chart (The Hot 100 combines radio play, digital sales, and streaming), but barely increases in airplay, while it loses its No. 1 spot on the Digital Songs chart.

In the meantime, Swift’s “I Knew You Were In Trouble” soars in downloads, though it only gains 5% in radio play. The song isn’t available for streaming, which makes its move to 4-2 on the Billboard Hot 100 all the more impressive.

Rihanna’s “Diamonds” loses a little of its shine as the former No. 1 slides 2-3. It pushes The Lumineers’ “Ho Hey” down one spot as well, to No. 4, while Justin Bieber’s “Beauty And A Beat” featuring Nicki Minaj holds at No. 5, according to Billboard.

And end-of-the-year download shopping spree (more about that in a minute) propels Psy’s “Gangnam Style” back into the top 10, as the track, which the S. Korean singer has retired,  leaps 17-6.

Ke$ha’s “Die Young” drops 6-7, as does Maroon 5’s “One More Night,” which falls to No. 8. Phillip Phillips’ “Home” stays at No. 9, while Macklemore and Ryan Lewis’s “Thrift Shop” holds at No. 10.



Fueled by holiday iTunes gift-card giving, a record 55.74 digital songs were sold last week. The amount skyrocketed past the previous record of 47.73 million sold the week ending Dec. 28 in 2008, according to Billboard. The Nielsen SoundScan sales week ends on a Sunday, so this year’s gift-card receivers had almost a full week of purchases counted in the tally.

Swift’s “I Knew You Were Trouble” topped the list with 582,000 copies, the fourth-biggest sales week for a song. (The record belongs to Flo Rida’s “Right Round” at 636,000).

Mars’ “Locked Out Of Heaven” comes in at No. 2 with 497,000, and “Gangnam Style” at No. 3 at 400,000.