WASHINGTON – The National Restaurant Association's Restaurant Performance Index gained 0.9 percent to hit in May. The RPI stood at 101.8, the third straight month that the index exceeded the 100 level and the third consecutive monthly gain.

"The May increase in the Restaurant Performance Index was driven by broad-based gains in the current situation indicators, most notably positive same-store sales and customer traffic results," said Hudson Riehle, senior vice president of the Research and Knowledge Group for the National Restaurant Association. "In addition, restaurant operators remain optimistic about continued sales growth and a majority plan to make a capital expenditure in the next six months."

The NRA said 63 percent of restaurant operators reported a same-store sales gain between May 2012 and May 2013, up from 49 percent who reported higher sales in April. Also, just 23 percent of operators reported a decline in same-store sales in May, down from 33 percent in April.

More restaurant operators report increases in customer traffic, with 47 percent of restaurant operators reporting higher customer traffic levels between May 2012 and May 2013, while 30 percent of operators said their traffic declined.

Capital spending climbed higher, with 52 percent of operators saying they made a capital expenditure for equipment, expansion or remodeling during the last three months, up from 47 percent who reported similarly in April.