ces 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 Operating income $20,000 12,000 8,000 5,000 $2,000 13. Using the degree of operating leverage, what is the estimated percent increase in operating income of a 5% Increase in sales? increase in operating income