OMAHA, Neb. (AP) — A survey of supply managers in a nine-state region of the Midwest and Plains is showing more signs of the coronavirus pandemic’s disruptive economic impact. A report released Monday says the Mid-American Business Conditions index sank in March to 46.7 — its lowest reading since September 2016. The survey’s confidence index plunged to a record low of 14.5. The survey results are compiled into a collection of indexes ranging from zero to 100. Survey organizers say any score above 50 suggests growth. A score below that suggests decline. The survey covers Arkansas, Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, Oklahoma and South Dakota.