Sales at department stores and supermarkets in Japan dropped in May from a year earlier, due partly to poor weather and a decrease in the number of holidays during the reporting month, industry groups said Monday.

Sales at 309 department stores run by 137 companies totaled 691.2 billion yen, down 3.3 percent after adjustment for the number of stores, the Japan Department Stores Association said.

It was the third consecutive monthly decline and the largest since the 4.3 percent fall recorded in November 1999, and came on the back of reduced demand from corporate customers, it said.