* Same-store sales at department stores climb 12.2 pct, y/y
* Supermarket same-store sales up 6.1 pct, y/y
MEXICO CITY, July 16 (Reuters) - Same-store sales for Mexican supermarkets and department and specialty stores on average rose 7.9 percent in June from a year earlier, retailers' association ANTAD said on Monday.
Sales at department stores open at least a year jumped 12.2 percent, while sales at supermarkets rose 6.1 percent compared with the same month in 2011.
ANTAD includes Mexico's biggest supermarket chains, Wal-Mart de Mexico and Organizacion Soriana, and it has more than 30,000 members.
Last week, Walmex said sales at its Mexican stores open at least a year rose 5.3 percent in June from the year earlier.