Rihanna's album "Anti" is No.1 on the US "Billboard 200". Overall, it says there were 54,000 units moved last week, which is low already for probably the biggest music market in the world. But since last year, they add up streams and units (I guess physical and download) = 1,500 plays of an album count as "one unit sold" apparently. In Rihanna's specific case, the breakdown shows 17,000 units sold, the rest comes from streaming. Forbes says it's the lowest selling No. 1 ever.