McDonald's Corp. (MCD) on Wednesday said same-store sales rose 6.5 percent in July, helped by breakfast menu offerings in the U.S.

Same-store sales, or sales at stores open at least thirteen months, is a key indicator of retailer performance since it measures growth at existing stores rather than newly opened ones.

Systemwide sales grew 11.7 percent during the month, or 7.8 percent in constant currencies.

U.S. same-store sales rose 4.3 percent, helped by breakfast and new food offerings and late-night hours.

European same-store sales rose 7.7 percent, helped by sales in France, Germany and the U.K.

Asia/Pacific, Middle East and Africa rose 9.9 percent, driven by results in Japan, Australia and China.

Year-to-date, same-store sales rose 6.8 percent, including a 4.7 percent rise in the U.S., a 7.9 percent rise in Europe and a 9.8 percent rise in Asia/Pacific, Middle East and Africa.