Both Telephone and Born This Way are very close to reach the milestone too, if Gaga performs them during her upcoming tour they will reach the milestone this year, this would bring her to have 5 - 9,000,000 PLUS SELLERS which would make her the only ARTIST IN HISTORY to accomplish that
I think this is pretty close but you MUST put the source for where your information comes from. Link us to the website/article to where you get these statistic from.