What was the percentage change in Total share-based compensation expense between 2018 and 2019?
{"Cost of salesproduct": {"July 27, 2019": 90, "July 28, 2018": 94, "July 29, 2017": 85}, "Cost of salesservice": {"July 27, 2019": 130, "July 28, 2018": 133, "July 29, 2017": 134}, "Share-based compensation expense in cost of sales .": {"July 27, 2019": 220, "July 28, 2018": 227, "July 29, 2017": 219}, "Research and development .": {"July 27, 2019": 540, "July 28, 2018": 538, "July 29, 2017": 529}, "Sales and marketing": {"July 27, 2019": 519, "July 28, 2018": 555, "July 29, 2017": 542}, "General and administrative": {"July 27, 2019": 250, "July 28, 2018": 246, "July 29, 2017": 236}, "Restructuring and other charges": {"July 27, 2019": 62, "July 28, 2018": 33, "July 29, 2017": 3}, "Share-based compensation expense in operating expenses": {"July 27, 2019": 1371, "July 28, 2018": 1372, "July 29, 2017": 1310}, "Total share-based compensation expense": {"July 27, 2019": 1591, "July 28, 2018": 1599, "July 29, 2017": 1529}, "Income tax benefit for share-based compensation .": {"July 27, 2019": 542, "July 28, 2018": 558, "July 29, 2017": 451}}
total_sharebased_compensation_expense_2019 = df["Total share-based compensation expense"]["July 27, 2019"]
total_sharebased_compensation_expense_2018 = df["Total share-based compensation expense"]["July 28, 2018"]
answer = (total_sharebased_compensation_expense_2019 - total_sharebased_compensation_expense_2018) / total_sharebased_compensation_expense_2018 * 100.0