[The following information applies to the questions displayed below) Oslo Company prepared the following contribution format income statement based on a sales volume of 1000 units (the relevant range of production is 500 units to 1,500 units): Sales Variable expenses Contribution serin Fixed expenses Net operating Income $ 20,000 12.000 8,000 6.000 52.000 13. Using the degree of operating leverage, what is the estimated percent increase in net operating income of a 5% increase in unit sales Increase in ne operating income %