What is the percentage change in nondeductible expenses in 2019 from 2018?
{"": {"2019": "", "2018": "(in thousands)", "2017": ""}, "Tax expense at U.S. statutory rate": {"2019": 10992, "2018": 3124, "2017": -3877}, "State income taxes, net of federal tax effect": {"2019": 1416, "2018": -237, "2017": -923}, "Nondeductible expenses": {"2019": 1720, "2018": 1186, "2017": -185}, "Change in reserve for tax contingencies": {"2019": -1468, "2018": -1047, "2017": -4435}, "Change in deferred tax asset valuation allowance": {"2019": -10007, "2018": 8784, "2017": 17374}, "Foreign rate differential (1)": {"2019": 2149, "2018": 5684, "2017": 9912}, "Tax credits": {"2019": -4767, "2018": -2656, "2017": -3459}, "Impact of U.S. Tax Reform": {"2019": "\u2014", "2018": -7053, "2017": "\u2014"}, "Global Intangible Low-Tax Income": {"2019": 8182, "2018": "\u2014", "2017": "\u2014"}, "Stock Based Compensation": {"2019": -448, "2018": 59, "2017": 16}, "Non-controlling interest in equity arrangements": {"2019": 1802, "2018": 99, "2017": "\u2014"}, "Other": {"2019": 1469, "2018": -850, "2017": 235}, "Provision for income taxes": {"2019": 11040, "2018": 7093, "2017": 14658}}
nondeductible_expenses_2019 = df["Nondeductible expenses"]["2019"]
nondeductible_expenses_2018 = df["Nondeductible expenses"]["2018"]
answer = ( nondeductible_expenses_2019 - nondeductible_expenses_2018 ) / nondeductible_expenses_2018 * 100.0