Rihanna scores 4th week at No.1 in US

Rihanna holds on at number one for a fourth week on the Billboard Hot 100 with 'Rude Boy'.
Behind Rihanna, the top ten remains virtually at a standstill, with the top eight all being non-movers this week.
Jason Derulo climbs back up from eleven to nine with 'In My Head', and Young Money slips from nine to ten with 'BedRock'. Ke$ha is the only artist to fall out the top ten with 'Tik Tok'.
Further down the chart, Usher's 'OMG' makes it's debut on the chart at 14, while Irish indie band The Script hold steady at 15 with 'Breakeven'.
La Roux makes another jump from 61 to 57 with 'Bulletproof', and Lady GaGa's 'Alejandro' is a new entry at 72.
The top ten singles in full
1. (1) Rihanna: 'Rude Boy'
2. (2) B.o.B ft. Bruno Mars: 'Nothin' On You'
3. (3) Train: 'Hey, Soul Sister'
4. (4) Lady Antebellum: 'Need You Now'
5. (5) Lady GaGa ft. Beyoncé: 'Telephone'
6. (6) Taio Cruz ft. Ludacris: 'Break Your Heart'
7. (7) Black Eyed Peas: 'Imma Be'
8. (8) Justin Bieber: 'Baby'
9. (11) Jason Derulo: 'In My Head'
10. (9) Young Money ft. Lloyd: 'BedRock''