13. please help

Oslo Company prepared the following contribution format income statement based on a sales volume of 1,000 units (the relevant range of production is 500 units to 1,500 units): Sales Variable expenses Contribution margin Fixed expenses Net operating income $ 40,000 26,000 14,000 8, 680 $ 5,320 13. Using the degree of operating leverage, what is the estimated percent increase in net operating income of a 5% increase in sales? (Round your intermediate calculations and final answer to 2 decimal places.) Increase in not operating income %