OMAHA, Neb. (AP) — A monthly economic survey index for nine Midwestern and Plains dropped in September, suggesting slowing economic growth in the months ahead.

A survey report issued Wednesday says the overall Mid-America Business Conditions Index dropped nearly three percentage points to 54.3, from 57.2 the previous month.

Creighton University economist Ernie Goss, who oversees the survey, says a drop in grain prices over the past year has led to a pullback in economic activity for the heavily agrarian region.

The survey results from supply managers are compiled into a collection of indexes ranging from zero to 100. Survey organizers 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.