Michigan retailers have high expectations for sales looking ahead to this spring and summer.In a recent report distributed by the Michigan Retailers Association, four out of five Michigan retailers expected sales from April to June to increase over last year.The Michigan Retail Index survey for March showed that 43 percent of the state’s retailers had increased sales compared to the same month last year, 34 percent recorded a decline in sales and 23 percent saw no change. In all, 49 percent of businesses expect an increase in inventory, 34 percent expect an increase in hiring, 27 percent expect an increase in prices and 46 percent expect an increase in promotions in the next three months.