What was the percentage change in Total selling, general and administrative expenses in 2019 from 2018?
{"Cost of sales -- Service cost": {"2019": 10.0, "2018": 10.5, "2017": 20.2}, "Cost of sales -- Total cost of sales": {"2019": 10.0, "2018": 10.5, "2017": 20.2}, "Selling, general and administrative expenses -- Service cost": {"2019": 1.5, "2018": 1.6, "2017": 3.9}, "Selling, general and administrative expenses -- Total selling, general and administrative expenses": {"2019": 1.5, "2018": 1.6, "2017": 3.9}, "Other expense -- Pension earnings, interest and deferrals": {"2019": 0.1, "2018": 2.1, "2017": 23.8}, "Other expense -- Curtailment charge": {"2019": "\u2014", "2018": "\u2014", "2017": 0.5}, "Other expense -- Total other expense": {"2019": 0.1, "2018": 2.1, "2017": 24.3}, "Other expense -- Net pension expense": {"2019": 11.6, "2018": 14.2, "2017": 48.4}}
total_expenses_2019 = df["Selling, general and administrative expenses -- Service cost"]["2019"]
total_expenses_2018 = df["Selling, general and administrative expenses -- Service cost"]["2018"]
answer = (total_expenses_2019 - total_expenses_2018) / total_expenses_2018 * 100.0