For a 12th straight month, Creighton University’s Rural Mainstreet Index fell below growth neutral, according to the August survey of bank CEOs in rural areas of a 10-state region dependent on agriculture and/or energy. The region’s overall reading for August sank to 40.9 from 41.3 in July. It was the lowest reading since November of last year. The index ranges between 0 and 100, with a reading of 50.0 representing growth neutral.