Japan's convenience store sales in September slipped 1.6 percent on yearly basis to 713.78 billion yen (about $7.28 billion), down for the third straight month,local media reported Monday.

The Japan Franchise Association attributed the fall partly to Typhoon Man-yi, which brought heavy rainfall in mid-September and prevented many people from coming to its members' retail outlets.

The average number of shoppers shrank 1.8 percent to 1,212.44 million. But the average expenditure per visitor increased 0.2 percent to 588.7 yen, the association noted.

The data cover 10 major convenience store chain operators belonging to the association.