It's Britney!

According to Zomba Label Group and Sony Music, Spears has sold over 84 million albums worldwide. She is ranked as the eighth best-selling female recording artist in the U.S. with 35 million copies of her albums certified by the RIAA, and is currently the fifth best-selling artist act of the decade in the country, as well as the top-selling female artist.

Spears is also ranked by Forbes 2009 issue as the 13th most powerful celebrity, and with earnings of over $35 million dollars in 2009, the 2nd-highest earning young musician of the year.

- courtesy of http://www.wikipedia.org