OMAHA, Neb. (AP) — A monthly economic survey index for nine Midwestern and Plains states rose slightly in August, suggesting growth is ahead.

A survey report issued Tuesday says the overall Mid-America Business Conditions Index inched up to 57.2 last month from 57.0 in July. The index had reached a three-year high of 60.6 in June.

Looking six months ahead, the business confidence portion of the overall index climbed to 60.4 from 60.0 in July. It had hit 63.6 in June.

The survey results from supply managers are compiled into a collection of indexes ranging from zero to 100. Survey organizers at Creighton University say any score above 50 suggests economic growth, while a score below that suggests decline.

The survey covers Arkansas, Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, Oklahoma and South Dakota.