What was the change in equity-based compensation between 2018 and 2019?
{"Deferred tax assets: -- Equity method investments": {"2019": 25.7, "2018": "$\u2014"}, "Deferred tax assets: -- Equity-based compensation": {"2019": 12.6, "2018": 9.2}, "Deferred tax assets: -- Deferred revenues": {"2019": 6.2, "2018": 14.8}, "Deferred tax assets: -- Interest rate swaps": {"2019": 5.6, "2018": "\u2014"}, "Deferred tax assets: -- Other": {"2019": 13.0, "2018": 11.4}, "Deferred tax assets: -- Total deferred tax assets": {"2019": 63.1, "2018": 35.4}, "Deferred tax liabilities: -- Goodwill and other intangibles": {"2019": -168.7, "2018": -178.9}, "Deferred tax liabilities: -- Deferred contract costs": {"2019": -40.3, "2018": -41.9}, "Deferred tax liabilities: -- Property, equipment and computer software": {"2019": -34.3, "2018": -28.0}, "Deferred tax liabilities: -- Other": {"2019": -5.1, "2018": -7.5}, "Deferred tax liabilities: -- Total deferred tax liabilities": {"2019": -248.4, "2018": -256.3}, "Deferred tax liabilities: -- Net deferred tax liability": {"2019": -185.3, "2018": -220.9}}
equity_based_compensation_2019 = df["Deferred tax assets: -- Equity-based compensation"]["2019"]
equity_based_compensation_2018 = df["Deferred tax assets: -- Equity-based compensation"]["2018"]
answer = equity_based_compensation_2019 - equity_based_compensation_2018