It's just because Live Your Life and Love the Way You Lie were monster smashes. 21 weeks isn't that bad. Especially since we all know Rihanna and her team care more about the number of #1's and not the weeks at #1 nowadays.
i don't wanna be alone forever
but i can be tonight
Bjork is an alien sent to observe us who inadvertently became a pop star in the process, initially mistakenly believing that we communicated exclusively with song and rhyme. The song "Human Behavior" is actually a status report home.