The following data refer to one year for Monroe Fabricators. Fill in the blanks. Direct materials inventory, January 1 Direct materials inventory, December 31 Work-in-process inventory, January 1 Work-in-process inventory, December 31 Finished goods inventory, January 1 SA 2,500 2,870 3,770 2,080 Finished goods inventory, December 31 380 Purchases of direct materials 16,170 Cost of goods manufactured during the year 54,010 Total manufacturing costs Cost of goods sold 55,710 Gross margin 47,71 Direct labor Direct materials used 14,690 Manufacturing overhead 13,920 Sales revenue