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 $ 25,400 Variable expenses 13,800 Contribution margin 11,600 Fixed expenses 7,772 Net operating income $ 3,828 Required: Using the degree of operating leverage, what is the estimated percent increase in net operating income of a 5% increase in sales? (Do not round intermediate calculations. Round