What was the increase / (decrease) in Free Cash flow from 2018 to 2019?
{"Financial guidelines -- Revenue": {"Actual Fiscal 2018 (1) $": 2147.0, "Revised projections (2) Fiscal 2019 (constant currency) (3)": 6, "Actual Fiscal 2019 (constant currency) (3) $": 2294.0, "Actual Fiscal 2019 (constant currency) (3) %": 6.8, "Achievement of the projections Fiscal 2019": "Achieved"}, "Financial guidelines -- Adjusted EBITDA": {"Actual Fiscal 2018 (1) $": 1007.0, "Revised projections (2) Fiscal 2019 (constant currency) (3)": 8, "Actual Fiscal 2019 (constant currency) (3) $": 1092.0, "Actual Fiscal 2019 (constant currency) (3) %": 8.5, "Achievement of the projections Fiscal 2019": "Achieved"}, "Financial guidelines -- Acquisitions of property, plant and equipment": {"Actual Fiscal 2018 (1) $": 458.0, "Revised projections (2) Fiscal 2019 (constant currency) (3)": 450, "Actual Fiscal 2019 (constant currency) (3) $": 425.0, "Actual Fiscal 2019 (constant currency) (3) %": -7.1, "Achievement of the projections Fiscal 2019": "Surpassed"}, "Financial guidelines -- Capital intensity": {"Actual Fiscal 2018 (1) $": 21.3, "Revised projections (2) Fiscal 2019 (constant currency) (3)": 20, "Actual Fiscal 2019 (constant currency) (3) $": 18.5, "Actual Fiscal 2019 (constant currency) (3) %": "-", "Achievement of the projections Fiscal 2019": "Surpassed"}, "Financial guidelines -- Free cash flow": {"Actual Fiscal 2018 (1) $": 302.0, "Revised projections (2) Fiscal 2019 (constant currency) (3)": 38, "Actual Fiscal 2019 (constant currency) (3) $": 453.0, "Actual Fiscal 2019 (constant currency) (3) %": 50.0, "Achievement of the projections Fiscal 2019": "Surpassed"}}
free_cash_flow_2019 = df["Financial guidelines -- Free cash flow"]["Actual Fiscal 2019 (constant currency) (3) $"]
free_cash_flow_2018 = df["Financial guidelines -- Free cash flow"]["Actual Fiscal 2018 (1) $"]
answer = free_cash_flow_2019 - free_cash_flow_2018