Sales at convenience stores across the nation fell 1.1 percent in August from a year earlier on a same-store basis, marking the 14th month of year-on-year declines, the Japan Franchise Association said Friday.

But on an all-store basis, including new stores, sales increased 3.4 percent to 632.15 billion yen, bolstered by brisk sales of soft drinks, ice cream and other summer goods, the association said.

The number of customers rose both on a same- and all-store basis thanks to fine weather, but overall sales were down as per-customer spending continued to fall, it said.

Average per-customer spending fell 2.1 percent on a same-store basis and 2.3 percent on an all-store basis.

The sales data covered a total of 36,877 outlets run by 14 major convenience-store operators.