Remember iTunes? Digital music downloads may not be dead yet, but the format is quickly following the CD in its decline. New numbers from Nielsen show that digital album sales in the U.S. declined by 9 percent in 2014, to 106.5 million, down from 117.6 in 2013. Including CDs, album sales even fell 11 percent. Digital song sales are also down 11 percent, with iTunes & Co. selling 1.1 billion tracks, down from 1.26 billion in 2013. But there’s also good news for the music biz: On-demand streaming was up 54 percent over 2013, with 164 billion songs streamed throughout the year.