Refer to the following mentioned data. Net sales (In millions) 2017 2016 2015 $34,964 $30, 206 $26,337 14,914 13,287 13, 402 $20,050 $16, 919 $12,935 Cost of products sold Gross margin Required: a. Calculate the gross profit ratio for each of the past three years. (Round your answers to 2 decimal places.) 2017 2016 57 % 56.01% 49.11% 2015 b. Assume that Campbell's net sales for the first four months of 2018 totaled $12.73 billion Calculate an estimated cost of goods sold and gross profit for the four months, using the gross profit ratio for 2017 (Round intermediate calculations to 2 decimal places. Enter your answers in millions rounded to nearest whole number (.e., 5,000,000 should be entered as 5).) Cost of goods sold Gross profit million million