Compared to the actual sales?
For example:
Britney
Femme Fatale
Certified: 1x Platinum
Actual sales: 788,000
...Baby One More Time
Certified: 14x Platinum
Actual sales: 10.6 million
Oops I Did It Again
Certified: 10x Platinum
Actual sales: 9.2 million
Katy Perry
Prism
Certified: 2x Platinum
Actual sales: 1.68 million
Other examples of overcertified albums?
