Bookstore sales fell 1.0% in May, to $953 million, according to preliminary estimates released Monday morning by the U.S. Census Bureau. May was the second consecutive month that bookstore sales declined and reflect in part the strong sales of the Fifty Shades trilogy last year. For the first five months of 2013, bookstore sales were nearly flat with 2012, up 0.2% to $5.24 billion.

For the entire retail sector, sales were up 5.0% in May and 3.7% for the first five months of the year.