Required information [The following information applies to the questions displayed below.) 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 $ 85,000 59,500 25,500 20,400 $ 5,100 13. Using the degree of operating leverage, what is the estimated percent increase in net operating income of a 5% increase in unit sales? (Round your intermediate calculations and final answer to 2 decimal places.) Increase in net operating income %