Bookstore sales declined 6.5% this September, compared to September 2016, according to preliminary figures released by the U.S. Census Bureau Wednesday morning. Sales in September were $1.01 billion, down from $1.8 billion a year ago.

The poor September performance in bookstore sales, for the second consecutive month, showed a significant decline compared to the prior year. In August bookstore sales tumbled 10.9%, compared to a year ago.

The 6.5% drop in September contributed to a 2.8% drop in bookstore sales for the January-September period in 2017, compared to the same period last year. Sales in the first nine months of the year were $8.15 billion, down from $8.38 billion in the 2016 period.

Sales for the full retail market were up 4.7% in September and increased 3.9% in the first nine months of 2017 over the comparable period in 2016.