Utada cds seem to sell more however her popularity has gone down faster than ayu's.Heart station is Utada's fifth japanese studio album and it sold,to my understanding,about 974,317 in japan.In ayu's case her fifth studio album Rainbow sold,to my understaniding,almost 2 million copies.While ayu's latest album,Guilty, sold less than Utada's latest album it still sold a lot for a nine studio album when japanese people are said to be rather tired of Ayu.Maybe you guys dont undertsand were I'm coming from but I think that Utada's popularity has gone down rather fast if we are taking sales wise even if she does seem to sell more.
However forgeting about the sales and everything personally Ayu is the Queen to me.
