Convenience store sales in May rose 1 percent from a year earlier to ¥620.35 billion on a same-store basis, increasing for the 13th consecutive month due partly to continuing strength in cigarette sales.

The number of visitors to convenience stores was up 2.5 percent to 1.09 billion, rising for the 14th straight month, but purchases per person were down 1.5 percent at ¥570.6, falling for the sixth month in a row, the Japan Franchise Association said Monday.

Tobacco sales have grown since taspo smart cards, designed to prevent minors from buying cigarettes from vending machines, were introduced last July. Many smokers without the age-identification cards continued buying cigarettes at convenience stores instead of using vending machines.

Another item that sold well was protective masks to guard against the spread of swine flu, the association said.