The National Restaurant Association's Restaurant Performance Index remained flat in October from the previous month, as lower foot traffic and sales offset improved outlook from restaurant operators.

The RPI is a monthly composite that tracks the health of, and outlook for, the restaurant industry. In October, its number fell slightly to an even 100 from September's 100.1, according to a release from the association Wednesday.

Anything above 100 generally indicates that the industry is in a period of expansion, and anything below 100 indicates signs of contraction.

Although sales results were somewhat softer in October, restaurant operators reported net positive same-store sales for the fifth consecutive month, Hudson Riehle, senior vice president of the Research and Knowledge Group for the National Restaurant Association, said in a statement. 

In addition, each of the four forward-looking indicators improved in October, which pushed the Expectations Index to its highest level in four months.

The RPI consists of two indexes: first, the Current Situation Index -- measuring trends in same-store sales, traffic, labor and capital expenditures. This stood at 99.5 in October, down 0.6 percent from September. It was also the third time in the last four months that the Current Situation Index was below 100, signifying contraction.

Second, there is the Expectation Index -- measuring restaurant operators' six-month outlook for the same four trends. This stood at 100.5 in October, up 0.4 percent from September and also the highest level in four months. This means a positive outlook among restaurant operators for the near term.

While restaurant operators reported positive same-store sales for the fifth consecutive month, the gains marked a decrease from September. Traffic, too, was down.

Thirty-seven percent of operators reported higher traffic, while 39 reported a decline. This compares to 43 percent reporting higher traffic and 33 percent reporting a decline in September, respectively.

But for the first time in four months, operators were optimistic about the future of the United States economy. Twenty-six percent said they anticipate the economy to improve in the next six months, up from 22 percent in September.