Lady Gaga took the top spot by earning $80 million over just the past 12 months, despite the singer's lucrative "Born This Way Ball" tour being cut short due to the singer's widely-reported hip injury forcing her from the road. Her staggering social media presence (she has 38 million followers on Twitter alone) is also cited as a deciding factor in Gaga owning the No. 1 position.

Hot on the heels of Gaga is superstar Beyonce, whose imminent "Mrs. Carter World Tour" (which recently added more dates) is thrusting her back into the pop music spotlight, after she spent most of last year raising her daughter with rap mega-mogul Jay-Z (he's No. 32 on the list), Ivy Blue.

At No. 3 is stalwart music money-maker Madonna, who still dominates the concert stage, with her massive tour behind the album MDNA generating a cool $305 million at the box office (it earned Madge the Billboard Music Award for Top Touring Artist in 2013).