WASHINGTON — The National Restaurant Association’s Restaurant Performance Index declined in September to 100.4, down 0.3% from August. Despite the decline September was the 11th consecutive month the R.P.I. was above 100, indicating expansion in the index of key industry indicators.

“Although restaurant operators reported softer same-store sales and customer traffic levels in September, they are somewhat more bullish about sales growth in the months ahead,” said Hudson Riehle, senior vice-president of the Research and Knowledge Group at the N.R.A. “Forty-five per cent of restaurant operators expect their sales to improve in the next six months while only 11% expect weaker sales.”

Also, even though restaurant operators had positive same-store sales for the 16th consecutive month, results were softer than in recent months. Forty-five per cent of operators had a same-store sales gain between September 2011 and September 2012, down from 61% in August, and 35% of operators had lower same-stores sales in September, up 25% from August.

Restaurant operators also reported a net decline in customer traffic levels in September with 36% of operators having higher customer traffic compared with the previous year, down from 47% who had positive traffic in August. In addition, 41% of operators had lower customer traffic in September, up from 32% in August.

The expectations index measuring operators six-month outlook on industry indicators was at 100.9 in September, up 0.2% from August but below stronger levels reached during the first half of 2012.

Operators are encouraged sales levels will improve in coming months with 45% of operators expecting to have higher sales in six months, up from 40% last month and the strongest level in three months. Only 11% of operators expect their sales volume in six months will be lower than it was during the same period of the previous year.

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