Use Exhibit 5.1 and assume the 2015 Estimated sale (revenue) is 95. Assuming we're forecasting using the percentage of sale approach and 2013 gross margin data, estimate 2015 Cost of Sales. Round to 2 decimal places. Median Firm ROA TABLE 5.1 Most profitable and least profitable U.S. industries: 2005-2014. Most Profitable Industries Median Firm ROA Least Profitable Industries Tobacco Products 18% Chemicals and Allied Products Building Materials, Retall 16% Metal Mining Leather and Leather Products 13% Mining and Quarrying Apparel and Accessory Stores 11% Building Construction Apparel 10% Oil and Gas Extraction -25% -14% -4% -2% - 1%