I think its universal Spears biggest 4th hits are: "Baby one more time", "Oops I did it again", "Toxic" and "Womanizer".
Which one is the 2nd or 3rd one is debatable so the order could be different for each person, but those are officialy her biggest 4 hits.
Now the question is which is her 5th biggest hit of her career rouding the top 5?.
Coud it be "Me against the music" the underperforming US single that smashed nearly every international chart?
Coud it be "Everytime" the biggest ballad of her career?
Could it be "Circus" with 5,5M singles sold across the globe despite not having impressive WW peaks on the charts?
Is it "Till the world ends", the song that found longevity almost everywhere with the exception of Uk and Germany?
Which is her 5th biggest hit of her career?
I love the song, but really?
