What was the percentage change in the tax charge in the income statement?
{"": {"2019": "$ million", "2018": "$ million"}, "Current income tax -- UK tax": {"2019": 0.3, "2018": 0.1}, "Current income tax -- Foreign tax": {"2019": 9.2, "2018": 6.2}, "Current income tax -- Amounts underprovided/(overprovided) in previous years": {"2019": 0.3, "2018": -1.2}, "Current income tax -- Total current income tax charge": {"2019": 9.8, "2018": 5.1}, "Deferred tax -- Recognition of deferred tax assets": {"2019": -1.5, "2018": -0.8}, "Deferred tax -- Reversal of temporary differences": {"2019": 3.5, "2018": 1.4}, "Deferred tax -- Adjustments in respect of prior years": {"2019": -0.2, "2018": -0.3}, "Deferred tax -- Total deferred tax charge": {"2019": 1.8, "2018": 0.3}, "Deferred tax -- Tax charge in the income statement": {"2019": 11.6, "2018": 5.4}}
tax_charge_2019 = df["Deferred tax -- Tax charge in the income statement"]["2019"]
tax_charge_2018 = df["Deferred tax -- Tax charge in the income statement"]["2018"]
answer = (tax_charge_2019 - tax_charge_2018) / tax_charge_2018 * 100.0