Falls Corporation believes that Utility Expense is a mixed cost. The following cost data is available for the past year. ons Month January February March April May June July August September October November December Units 15,200 12,500 17,500 16,000 23,500 21,000 30,000 27,500 22,000 15,450 14,900 13,700 Costs $36,375 $38,000 $41.750 $42,360 $55,080 $48,100 $59,000 $56,800 $48,700 $37,120 $37,020 $30,563 Using the high-low method, what is variable cost per unit? (NOTE: Enter a number with two decimal places, do not add commas or dollar signs. Enter a minus sign for a negative number)