 At the time of its release , Daydream became Carey 's best @-@ reviewed album . Critics universally praised her matured lyrics and songwriting , as well as her musical direction . The album became an international success , debuting at number one in nine different countries , and in the top five in almost every major music market . Daydream became Carey 's second album to be certified diamond by the Recording Industry Association of America ( RIAA ) , denoting shipments of ten million copies in the United States . Aside from its success in the United States , the album made the top five of the best @-@ selling albums in Japan by a non @-@ Asian artist , with 2 @.@ 1 million copies sold . Daydream remains one of the best @-@ selling albums of all time , with 25 million copies sold worldwide . 
