What was the percentage change in the Total current expense between 2017 and 2018?
{"Pretax (loss) income: -- U.S.": {"2019": -593.4, "2018": -127.3, "2017": -279.3}, "Pretax (loss) income: -- Foreign": {"2019": 797.9, "2018": 864.6, "2017": 369.1}, "Pretax (loss) income: -- ": {"2019": 204.5, "2018": 737.3, "2017": 89.8}, "Current (benefit) expense: -- U.S. Federal": {"2019": -98.0, "2018": 369.4, "2017": 21.3}, "Current (benefit) expense: -- State": {"2019": -5.3, "2018": 0.5, "2017": 1.0}, "Current (benefit) expense: -- Foreign": {"2019": 14.1, "2018": 60.8, "2017": 23.8}, "Current (benefit) expense: -- Total current (benefit) expense": {"2019": -89.2, "2018": 430.7, "2017": 46.1}, "Deferred expense (benefit): -- U.S. Federal": {"2019": 11.9, "2018": 82.5, "2017": -114.7}, "Deferred expense (benefit): -- State": {"2019": 0.6, "2018": 0.1, "2017": -5.4}, "Deferred expense (benefit): -- Foreign": {"2019": -74.7, "2018": -31.4, "2017": -6.8}, "Deferred expense (benefit): -- Total deferred (benefit) expense": {"2019": -62.2, "2018": 51.2, "2017": -126.9}, "Deferred expense (benefit): -- Total Income tax (benefit) provision": {"2019": -151.4, "2018": 481.9, "2017": -80.8}}
total_current_expense_2018 = df["Current (benefit) expense: -- Total current (benefit) expense"]["2018"]
total_current_expense_2017 = df["Current (benefit) expense: -- Total current (benefit) expense"]["2017"]
answer = (total_current_expense_2018 - total_current_expense_2017) / total_current_expense_2017 * 100.0