Madonna\'s MDNA has suffered the biggest second-week drop in sales for a number one album in US chart history. The record debuted at the top of the Billboard chart last week, but has now fallen to number eight. That reflects a drop in sales from 359,000 in week one to 48,000 copies in week two - a decline of 86.7%. Lady Gaga previously held the title. Her 2011 album Born This Way fell from 1.1 million copies in its first week to 174,000 in week two, an 84% decline. MDNA was knocked off the top spot this week in the US and in the UK by Nicki Minaj\'s album Pink Friday - Roman Reloaded, which went straight in at number one in both countries. The rapper features twice on Madonna\'s album, along with the singer\'s 15-year-old daughter, Lourdes, who sings on track Superstar. Neilsen Soundscan, which compiles the chart, predicted MDNA\'s large fall, as its first-week sales included albums given away with concert tickets, as well as pre-orders from iTunes. Also, without a current hit single or any recent promotion on Madonna\'s part, the drop was bound to be significant. In the UK, MDNA fell from number one to number seven this week in The Official Album Chart. Madonna has also announced her ninth concert tour with 90 dates starting in Israel at the end of May 2012 and finishing in Australia in early 2013. From: BBC