After three declining months, an index that gauges the health and outlook of the U.S. restaurant industry moved up in August.

The Washington, D.C.-based National Restaurant Association’s Restaurant Performance Index finished at 101.9, up 1 percent from July and the first gain in three months.

It also marked the 18th consecutive month the index was above 100, which signifies expansion in key industry indicators, according to a news release.

“The August gain in the RPI was fueled by stronger same-store sales and customer traffic results, aided by continued improving economic conditions,” Hudson Riehle, senior vice president of the association’s research and knowledge group, said in the release. “Looking forward, restaurant operators remain generally optimistic about continued sales growth, while a majority plans to make a capital expenditure in the next six months. However, operators still report food costs and government among top challenges that continue to negatively affect the operating environment.”

Restaurant index rebounds in AugustThe index measures the industry’s health against a steady-state level of 100. Values of more than 100 indicate periods of expansion for key economic indicators, whereas values less than 100 represent periods of contraction.

The index also comprises two components: the current situation index and the expectations index.

The current index, which measures same-store sales, traffic, labor and capital expenditures, stood at 101.8 in August. That’s up 1.1 percent from July and the strongest level in three months.

The expectations index, which measures restaurant operators’ six-month outlook of same-store sales, employees, capital expenditures and business conditions, stood at 102.1 in August, up 0.9 percent from July.

It also was the highest level in three months and represented the 22nd consecutive month in which the expectations index exceeded 100, meaning operators were generally optimistic about business conditions, according to the release.