Let's try this with part of the 2024 income statement. We will assume 40% of the bookstore's total operating expenses should be allocated to the service department, except for Cost of Goods Sold which is 10%: Sales Revenue Cost of Goods Sold Gross Margin UCW Bookstore Income Statement For the Year Ended Dec 31, 2024 $472,500 180,000 292,500 Salary Expense Rent Expense Utilities expense Depreciation expense Total Expenses Net Income 180,000 60,000 30,000 9,600 279,600 $12,900 Item as a percent of Sales Revenue Using Sales Revenue as the base number, let's calculate the empty column. Profit Margin