Katy Perry Rules Hot 100 With 'Firework'

Katy Perry has clinched the Christmas number one single in America by scoring a third week at the top of the charts with "Firework". The newlywed has kept a surging Bruno Mars from the top of the Billboard charts - his "Grenade" moves up to two on the new countdown. Mars and Rihanna both score top 10 doubles - Mars' "Just the Way You Are" moves up a spot to six, while Rihanna's "What's My