Your comparison of the gross margin percent for Jackels Drugs for the years 2016 through 2019 indicates a significant decline. This is shown by the following information: (Click the icon to view the data and additional discussion with the controller.) The following additional information is obtained from independent sources and the client's records as a means of investigating the controller's explanations: 1 (Click the icon to view the additional information.) Requirement a. Evaluate the explanation provided by Averett. Show calculations to support your conclusions. Begin by computing the gross margin percentage for drug and nondrug sales for 2019 through 2016. (Round your answers to the nearest tenth percent, XX.X%.) Gross margin % - Gross margin % - Year Drug sales Nondrug sales 2019 % 2018 % 2017 % 2016 % do do do % % % %