What is the change in Additions for tax benefits related to the current year from December 31, 2018 to 2019?
{"Balance at beginning of year": {"2019": 112.2, "2018": 114.8, "2017": 136.7}, "Acquired balances": {"2019": 15.5, "2018": "\u2014", "2017": "\u2014"}, "Additions for tax benefits related to the current year": {"2019": 9.4, "2018": 7.4, "2017": 23.6}, "Additions for tax benefits of prior years": {"2019": 8.0, "2018": 2.8, "2017": 4.7}, "Reductions for tax benefits of prior years": {"2019": -0.2, "2018": -1.9, "2017": -1.6}, "Lapse of statute": {"2019": -8.2, "2018": -10.9, "2017": -16.3}, "Settlements": {"2019": -6.7, "2018": "\u2014", "2017": -4.9}, "Change in rate due to U.S. Tax Reform": {"2019": "\u2014", "2018": "\u2014", "2017": -27.4}, "Balance at end of year": {"2019": 130.0, "2018": 112.2, "2017": 114.8}}
additions_2019 = df["Additions for tax benefits related to the current year"]["2019"]
additions_2018 = df["Additions for tax benefits related to the current year"]["2018"]
answer = additions_2019 - additions_2018