The National Restaurant Association’s performance index has fallen for the third straight month, reflecting concerns over the economy.

Despite the decline, the August index still suggests the restaurant industry is growing.

The Washington, D.C.-based NRA’s Restaurant Performance Index (RPI) was 100.5 in August, down 0.2% from July, according to an association news release.

The index did, however, top 100 for the sixth straight month. Index values above 100 mean that key industry indicators are in a period of expansion.

“The August decline in the RPI was due almost entirely to a dip in the expectations indicators, with restaurant operators becoming less bullish about sales growth and the economy in the months ahead,” Hudson Riehle, senior vice president of the association’s Research and Knowledge Group, said in the release. “In contrast, operators reported positive same-store sales and customer traffic levels in August, and a majority of operators reported capital expenditures for the fourth consecutive month.”

The NRA’s Current Situation Index, which measures trends in same-store sales, traffic, labor and capital expenditures, stood at 100.7 in August, up .6% from July and the first increase in three months.