What is the percentage change in income from discontinued operations (net of tax) from 2017 to 2019?
{"Loss on sale of business": {"2019": "$\u2014", "2018": "$\u2014", "2017": -1.6}, "Income from discontinued operations before income taxes and equity method investment earnings": {"2019": 0.9, "2018": 0.4, "2017": 3.9}, "Income before income taxes and equity method investment earnings .": {"2019": 0.9, "2018": 0.4, "2017": 2.3}, "Income tax expense (benefit) .": {"2019": "\u2014", "2018": 0.5, "2017": -0.3}, "Income (loss) from discontinued operations, net of tax": {"2019": 0.9, "2018": -0.1, "2017": 2.6}}
income_2019 = df["Income from discontinued operations before income taxes and equity method investment earnings"]["2019"]
income_2017 = df["Income (loss) from discontinued operations, net of tax"]["2017"]
answer = (income_2019 - income_2017) / income_2017 * 100.0