What was the percentage change in Total stock-based compensation expense between 2018 and 2019?
{"Stock-based compensation expense - Property": {"2019": 1.8, "2018": 2.4, "2017": 2.1}, "Stock-based compensation expense - Services": {"2019": 1.0, "2018": 0.9, "2017": 0.8}, "Stock-based compensation expense - SG&A": {"2019": 108.6, "2018": 134.2, "2017": 105.6}, "Total stock-based compensation expense": {"2019": 111.4, "2018": 137.5, "2017": 108.5}, "Stock-based compensation expense capitalized as property and equipment": {"2019": 1.6, "2018": 2.0, "2017": 1.6}}
total_stockbased_compensation_expense_2019 = df["Total stock-based compensation expense"]["2019"]
total_stockbased_compensation_expense_2018 = df["Total stock-based compensation expense"]["2018"]
answer = (total_stockbased_compensation_expense_2019 - total_stockbased_compensation_expense_2018) / total_stockbased_compensation_expense_2018 * 100.0