Fifty Shades of Grey is the bestselling book of the year by a margin of over a million copies, but according to Nielsen BookScan's sales numbers for the week ended June 24, sales of the book are down 5% in the past week. That doesn't mean the book is slipping--the trilogy and the box set are still the top four books on the overall bestseller list according to BookScan--but the first book in the series has fallen from 303,540 copies sold last week to 288,361 copies sold this week.

The second and third books in the trilogy, Fifty Shades Darker and Fifty Shades Freed, fell 6% in the past week. But the box set, packaging all three books together (which we reported started hot last week), has dropped 45% in just its second week on the bestseller list. The box set sold 83,746 copies for the week ending June 17 and 46,131 copies for the week ending June 24, according to the outlets tracked by BookScan.

After the first four spots on the bestseller list, Suzanne Collins's Mockingjay comes in at number five with 36,344 copies sold in the week ending June 24.