What was the sum of the percentages of total net sales between Honda Motor Co. and Toyota Motor Corporation in 2017?
{"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}}
total_net_sales_honda = df["Honda Motor Co."]["2017"]
total_net_sales_toyota = df["Toyota Motor Corporation"]["2017"]
answer = total_net_sales_honda + total_net_sales_toyota