2, How to Save a Life, and the self-titled The Fray.
I would guess around 75 million worldwide. Am I on target?
Sunburn, Origin of Symmetry, Absolution, Black Holes and Revelations, (HAARP), (Hullabaloo), and The Resistance. So that makes seven (unless you don't want to count HAARP and Hullabaloo then it is...
Megadeth sold about 25 million albums.