What is the percentage change in share-based compensation for sales and marketing between 2018 and 2019?
{"Cost of revenues": {"2019": 8741, "2018": 4982, "2017": 3735}, "Research and development": {"2019": 23132, "2018": 14975, "2017": 9550}, "Sales and marketing": {"2019": 38325, "2018": 27324, "2017": 16015}, "General and administrative": {"2019": 31156, "2018": 20807, "2017": 12760}, "Total share-based compensation expense": {"2019": 101354, "2018": 68088, "2017": 42060}}
share_based_compensation_2019 = df["General and administrative"]["2019"]
share_based_compensation_2018 = df["General and administrative"]["2018"]
answer = (share_based_compensation_2019 - share_based_compensation_2018) / share_based_compensation_2018 * 100.0