WASHINGTON — The National Restaurant Association’s Restaurant Performance Index was at 101.3 in January, a decline from 102.2 in December, but this level still represented the third consecutive month the R.P.I. has indicated industry expansion.

“Although the Restaurant Performance Index dipped somewhat from December’s nearly six-year high, it remained solidly in positive territory,” said Hudson Riehle, senior vice-president of the Research and Knowledge Group for the N.R.A. “Restaurant operators reported positive same-store sales for the eighth consecutive month, and a majority of them expect business to continue to improve in months ahead.”

Fifty-six per cent of operators reported a same-store sales gain in January, and only 26% reported a same-store sales decline. This was down slightly from December when 69% of operators reported a sales gain and 18% reported lower sales.

In addition, 46% of operators reported higher customer traffic levels in January with 30% reporting a traffic decline. This also was down from December when 57% of operators reported higher customer traffic with 23% reporting a traffic decline.

Also, 53% of restaurant operators expect to have higher sales in six months, up from 51% who said the same during the previous month. Just 7% of operators expect sales volume in six months to be lower than what it was during the same period of the previous year, equal to levels during the previous month.

Operators also are relatively optimistic about the direction of the overall economy with 37% of operators saying they expect economic conditions to improve in six months, although this was down from 39% who said the same last month. In addition, 11% of operators said they expect economic conditions to worsen during the next six months.