Engberg Company installs lawn sod in home yards. The company's most recent monthly contribution format income statement follows: Sales Variable expenses. Contribution margin Fixed expenses Net operating income Required: Percent of Amount Sales $ 133,000 53,200 100% 40 79,800 17,000 60% $ 62,800 1. What is the company's degree of operating leverage? 2. Using the degree of operating leverage, estimate the impact on net operating income of a 15% increase in unit sales. 3. Construct a new contribution format income statement for the company assuming a 15% increase in unit sales.