According to research by Music Week magazine, the Scottish singer's album The Gift sold 3.7 million copies overseas whereas her debut album I Dreamed A Dream sold six million.
Sade had the second best-selling album with Soldier of Love selling 2.3 million copies while Mumford and Sons' album Sigh No More, which won best album at the Brits earlier this month, sold 1.3 million copies.
Other albums in the list include Muse's 2009 offering The Resistance, Phil Collins' cover album Going Back, Plastic Beach by Gorillaz and James Blunt's Some Kind of Trouble.