Harper Lee's 'Go Set a Watchman' tops 2015 US bestseller list

Harper Lee's second novel "Go Set a Watchman" topped the US bestseller list in 2015.

• Aprrox 6 million copy were sold in USA since 2015
• The second  bestseller in the list was Jeff Kinney’s Diary of Wimpy Kid series (1.48 million copies) 
•  And the third bestseller in the list was  British author EL James’ Grey: Fifty Shades of Grey as Told by Christian (1.4 million) respectively.