A monthly index of the Midwest rural economy declined again in December, the fourth straight month, reflecting weakness from lower agriculture and energy commodity prices and from downturns in manufacturing. The Creighton University Rural Mainstreet Index for December fell to 41.5 from November’s 43.7. The index ranges from 0 to 100. In the monthly survey, rural bank CEOs said they expect farmland prices to drop by another 5.9 percent in 2016. Cash sales of farmland also are expected to decline next year. Although rural hiring and rural bank loans were up, other economic indicators — checking account deposits, banker confidence and home and retail sales — were down. Iowa’s index was higher than six of the 10 states in the index because of increases in the price of farmland and new hiring.