V is Maroon 5’s fifth album to sell a million copies -- and now all five of their studio albums have reached the milestone. Their biggest selling effort remains their 2002 debut, Songs About Jane, which has sold 5.1 million. In total, Maroon 5 has sold 12.9 million albums in the U.S.
That's impressive.

They call them singles artist when selling 1M in 2014/2015 is not easy at all.
