What was the change in the Additions Charged to Costs and Expenses between 2017 and 2019?
{"Valuation allowance for deferred tax assets: -- Fiscal 2019": {"Balance at Beginning of Year": 204.5, "Additions Charged to Costs and Expenses": 16.2, "Additions Charged to Other Accounts": 175.8, "Deductions": -64.4, "Balance at End of Year": 332.1}, "Valuation allowance for deferred tax assets: -- Fiscal 2018": {"Balance at Beginning of Year": 210.1, "Additions Charged to Costs and Expenses": 36.2, "Additions Charged to Other Accounts": "$\u2014", "Deductions": -41.8, "Balance at End of Year": 204.5}, "Valuation allowance for deferred tax assets: -- Fiscal 2017": {"Balance at Beginning of Year": 161.8, "Additions Charged to Costs and Expenses": 15.2, "Additions Charged to Other Accounts": 37.6, "Deductions": -4.5, "Balance at End of Year": 210.1}}
additions_charged_2019 = df["Valuation allowance for deferred tax assets: -- Fiscal 2019"]["Additions Charged to Other Accounts"]
additions_charged_2017 = df["Valuation allowance for deferred tax assets: -- Fiscal 2017"]["Additions Charged to Other Accounts"]
answer = additions_charged_2019 - additions_charged_2017