If we assume sales remained constant from 2014, then the predictions have 25 at 9.2 million 1999 sales
And we know album sales are terrible compared to last year, so she could break 10 million 1999 sales first week
It really doesn't make since to translate 2015 to 2000 album sales because there so much to consider and selling 9.2 million first week is nearly impossible since there's no room to stock shelves at various stores with that many albums at once.
She'll have so many insane sales weeks to look forward to.
I actually think she'll have sold 60% of what 21 did, by January.
She's got:
Release week, Black Friday, Thanksgiving, the run-up to Xmas, Xmas week, and New Years.
Flo Rida sold a lot too, but his album flopped. I doubt I'm underestimating her first week sales specially since album sales are low as well.
And as we established 800x before with Adele since October 23rd. She is an exception to all the rules.
If Taylor swift can get close to breaking Britney's record LAST YEAR. Why are you doubting Adele who is literally a powerhouse and sold 30M albums since 2011 when "record sales are low"