"The Massacre" by 50 Cent ended as the best selling album that year..

The last time was in 2004:

Single: Yeah! - Usher featuring Lil Jon and Ludacris
Album: Confessions - Usher

That was absolutely Usher's year

I thought we were going by Soundscan year because Mariah definitely was #1 there.

next up 6 million.

Do you have some source?

I searched in Wikipedia LOL

Here's a quick source:
http://www.islanddefjam.com/artist/n...&artistid=7331

Read down.

But there are other sources out there.

Billboard and Soundscan have two different time measures. I remember 50 Cent benefited on Billboard but came up short on Soundscan because it counts December, the month in which Mariah passed him up.

Yeah, that always happens.. It's like last year California Gurls and Hey, Soul Sister fighting for the best-selling single

Ok, so that didn't happen since Mariah's domination in 2005, just 6 years ago

Yet, Tik Tok got it, sorta. California Gurls was the best selling song digitally in 2010, but I think that might be calendar year.

Bow to ADELE!