What is the % change in the balance at end of year from 2018 to 2019?
{"": {"2019": "in millions)", "2018": ""}, "Balance at beginning of year": {"2019": 3.0, "2018": 0.2}, "Additions for current year tax positions": {"2019": 1.5, "2018": 1.2}, "Additions for prior year tax positions": {"2019": 11.5, "2018": 1.7}, "Reductions as a result of settlement with tax authority": {"2019": -0.3, "2018": -0.1}, "Balance at end of year": {"2019": 15.7, "2018": 3.0}, "Interest and penalties included in balance": {"2019": 2.2, "2018": 0.1}, "Amount, if recognized, would impact the effective income tax rate": {"2019": 10.0, "2018": 1.8}, "Amount that could be settled within the next year": {"2019": 10.0, "2018": 1.9}}
balance_2019 = df["Balance at end of year"]["2019"]
balance_2018 = df["Balance at beginning of year"]["2019"]
answer = (balance_2019 - balance_2018) / balance_2018 * 100.0