What is the proportion of exercisable options over outstanding options as of May 26, 2019?
{"Outstanding at May 27, 2018": {"Number of Options (in Millions)": 5.1, "Weighted Average Exercise Price": 28.11, "Average Remaining Contractual Term (Years)": "", "Aggregate Intrinsic Value (in Millions)": ""}, "Exercised": {"Number of Options (in Millions)": -0.6, "Weighted Average Exercise Price": 20.75, "Average Remaining Contractual Term (Years)": "", "Aggregate Intrinsic Value (in Millions)": 7.9}, "Expired": {"Number of Options (in Millions)": -0.1, "Weighted Average Exercise Price": 29.84, "Average Remaining Contractual Term (Years)": "", "Aggregate Intrinsic Value (in Millions)": ""}, "Outstanding at May 26, 2019": {"Number of Options (in Millions)": 4.4, "Weighted Average Exercise Price": 29.0, "Average Remaining Contractual Term (Years)": 5.47, "Aggregate Intrinsic Value (in Millions)": 9.9}, "Exercisable at May 26, 2019": {"Number of Options (in Millions)": 4.1, "Weighted Average Exercise Price": 28.38, "Average Remaining Contractual Term (Years)": 5.32, "Aggregate Intrinsic Value (in Millions)": 9.9}}
exercisable_options = df["Exercisable at May 26, 2019"]["Number of Options (in Millions)"]
outstanding_options = df["Outstanding at May 26, 2019"]["Number of Options (in Millions)"]
answer = exercisable_options / outstanding_options