What was the percentage change in the Additions related to prior years tax positions in 2019 from 2018?
{"": {"2019": "", "2018": "(in millions)", "2017": ""}, "Balance at beginning of fiscal year": {"2019": 566, "2018": 501, "2017": 490}, "Additions related to prior years tax positions": {"2019": 13, "2018": 14, "2017": 40}, "Reductions related to prior years tax positions": {"2019": -101, "2018": -11, "2017": -9}, "Additions related to current year tax positions": {"2019": 98, "2018": 105, "2017": 70}, "Settlements": {"2019": -2, "2018": -7, "2017": -4}, "Reductions due to lapse of applicable statute of limitations": {"2019": -32, "2018": -36, "2017": -86}, "Balance at end of fiscal year": {"2019": 542, "2018": 566, "2017": 501}}
additions_2019 = df["Additions related to prior years tax positions"]["2019"]
additions_2018 = df["Additions related to prior years tax positions"]["2018"]
answer = ( additions_2019 - additions_2018 ) / additions_2018 * 100.0