Equivalent Album Sales from Chartmasters:
Mariah Carey - 19,928,000
...Baby One More Time - 32,726,000
Emotions - 13,296,000
Oops!... I Did It Again - 24,729,000
Music Box - 34,707,000
Britney - 13,542,000
Merry Christmas - 20,132,000
In the Zone - 13,531,000
Daydream - 32,312,000
Blackout - 5,561,000
Butterfly - 13,599,000
Circus - 8,190,000
Rainbow - 9,415,000
Femme Fatale - 4,965,000
Glitter - 2,254,000
Britney Jean - 1,596,000
Charmbracelet - 3,018,000
Glory - 1,084,000
The Emancipation of Mimi - 11,042,000
B10 - ?
Comparing them album to album, Britney started out strong with her first 2 albums but seemed to fizzle out quickly. Whereas Mariah has showed much more longevity, outselling her with every subsequent album. And it's unlikely B10 will outsell Mariah's 10th album, TEOM. Mariah's hits (and even an album track) from her 11th and 12th album also went viral recently. So this begs the question, why is Mariah Carey more remembered and why does she have more longevity than Britney Spears? I LOVE them both but this is a VERY interesting topic.