Creighton University’s September Rural Mainstreet Index for Iowa fell to 39.9 from 42.3 in August, well below a level that would indicate growth. The farmland index for the state also fell, to 36.2 from 43.1. But the new-hiring index rose to 57.5 from 52.5 the month before. The overall index fell to its lowest level this year, with the survey of bank CEOs in a 10-state region sending the measure below growth-neutral for the region.