Engberg Company installs lawn sod in home yards. The companys most recent monthly contribution format income statement follows: Amount Percent of Sales Sales $ 86,000 100% Variable expenses 34,400 40% Contribution margin 51,600 60% Fixed expenses 38,700 Net operating income $ 12,900 Required: What is the companys degree of operating leverage? Using the degree of operating leverage, estimate the impact on net operating income of a 7% increase in unit sales. Construct a new contribution format income statement for the company assuming a 7% increase in unit sales