WASHINGTON (AP) — U.S. wholesale businesses increased their stockpiles by a modest amount in January as sales plunged by the largest amount in six years.

The Commerce Department says stockpiles held by wholesale businesses rose 0.3 percent in January after no change in December and a 0.8 percent November increase.

Sales dropped 3.1 percent in January following a 0.9 percent December decline. The January decline was the largest setback since sales fell 3.6 percent in March 2009 when the country was mired in the Great Recession. January marked the fourth consecutive month that sales have fallen.

Despite the string of declines in sales, economists remain optimistic that sales will rebound in coming months as consumer spending gets a boost from falling gas prices and healthy job gains.