What is the percentage change in EBITDA from 2017 to 2018?
{"": {"2019": 0.0, "2018": 0.0, "2017": 0.0, "2016": 0.0, "2015": 0.0}, "Revenue": {"2019": 171819.0, "2018": 140176.0, "2017": 110865.0, "2016": 93597.0, "2015": 80216.0}, "EBITDA": {"2019": 62721.0, "2018": 44869.0, "2017": 33254.0, "2016": 27430.0, "2015": 22697.0}, "EPS": {"2019": 40.57, "2018": 28.86, "2017": 21.7, "2016": 17.89, "2015": 12.47}, "Profit for the year": {"2019": 52893.0, "2018": 37489.0, "2017": 28077.0, "2016": 23020.0, "2015": 15398.0}, "Dividend declared - AU cents": {"2019": 34.0, "2018": 27.0, "2017": 23.0, "2016": 20.0, "2015": 16.0}, "Share price - AU$": {"2019": 34.2, "2018": 22.51, "2017": 8.57, "2016": 6.46, "2015": 4.43}, "STI Achievement": {"2019": 100.0, "2018": 131.0, "2017": 103.0, "2016": 97.0, "2015": 63.0}, "STI performance hurdles": {"2019": 70.0, "2018": 50, "2017": 70, "2016": 50, "2015": "Different metrics related to subscriber related to subscriber growth, EPS and Product development related to subscriber growth, EPS and Product development related to subscriber growth, EPS and Product development"}, "LTI Achievement": {"2019": 100.0, "2018": 100.0, "2017": 100.0, "2016": 100.0, "2015": 50.0}, "LTI performance hurdles": {"2019": 50.0, "2018": "EPS", "2017": "EPS", "2016": "EPS", "2015": 50}}
ebitda_2018 = df["EBITDA"]["2018"]
ebitda_2017 = df["EBITDA"]["2017"]
answer = ( ebitda_2018 - ebitda_2017 ) / ebitda_2017 * 100.0