What proportion of the total stock-based compensation expense is made up from the research and development operations in 2019?
{"Research and development expense: -- Stock option awards": {"2019": 8, "2018": 38}, "Research and development expense: -- RSU awards": {"2019": 13, "2018": 27}, "Research and development expense: -- ": {"2019": 21, "2018": 65}, "General and administrative expense: -- Stock option awards": {"2019": 12, "2018": 61}, "General and administrative expense: -- RSU awards": {"2019": 105, "2018": 104}, "General and administrative expense: -- ": {"2019": 117, "2018": 165}, "General and administrative expense: -- Total share-based compensation expense": {"2019": 138, "2018": 230}}
research_and_development_expense_2019 = df["Research and development expense: -- "]["2019"]
total_sharebased_compensation_expense_2019 = df["General and administrative expense: -- Total share-based compensation expense"]["2019"]
answer = research_and_development_expense_2019 / total_sharebased_compensation_expense_2019 * 100.0