this was hard to choose. katy had a phenomenal year with radio airplay w/ teenage dream's singles.
i have to say rihanna wins though. it is never easy to outsell as an urban artist so she wins on that alone. she outsold katy and grossed more on tour. she is very versatile: her singles all are superb sonically and all sounded different. love the way you lie, only girl, whats my name, s&m, california king bed, man down, cheers.