David Bowie's last album, "Blackstar," debuted number one on the Billboard charts, the first U.S. chart-topper for the late musician. Since it was released two days before Bowie died of cancer on Jan. 10, "Blackstar" has sold 174,000 copies, according to Nielsen Music. It's the best sales week for Bowie since Nielsen began electronically tracking music purchases in 1991. Bowie dislodged the previous No. 1, Adele's "25," which slipped to No. 2 after seven weeks on top.