What was the change in the percentage of total net sales from Honda Motor Co. between 2017 and 2018?
{"Cummins Inc.": {"2019": 16.1, "2018": 15.2, "2017": 13.4}, "Honda Motor Co.": {"2019": 11.6, "2018": 10.5, "2017": 11.2}, "Toyota Motor Corporation": {"2019": 9.6, "2018": 10.5, "2017": 10.2}}
honda_2018 = df["Honda Motor Co."]["2018"]
honda_2017 = df["Honda Motor Co."]["2017"]
answer = honda_2018 - honda_2017