Britney Spears and P!nk, from the past generation.
Taylor Swift, Lady Gaga, Rihanna and Katy Perry from the current generation.
Anyway it's not fair to compare popgirls year number-wise. I mean what if for example Adele releases her next album in 2040 and it smashes, does that mean she was successful for 30+ years even though she didn't release an album between 2011 and 2040?