Sorry guys.I was wrong about the year-end numbers in America.it sold 1.3 million on billboards year-end chart and was number 8.it had also topped 900k digital copies....see <- this article is one week ahead,that's why it's at 1-8-14) which means it sold 400k of the 500k American shipments.and it probably had another estimated 100k unsold shipments outside the states...which means it sold between 2-2.1 million in 2013
There shouldn't be a question as to which numbers to use. At the end of the day, it is which source is official and which isn't. Try using the International Federation of the Phonographic Industry (IFPI) or MediaTraffic on a school report and see which one your professor will accept as a credible source.
she'll climb next week ! 
I wonder if it will sell 5m at the end of the era 
