What percentage of total property and equipment, gross consist of leasehold improvements in 2018?
{"Computer equipment and software": {"Useful Life": 3, "2019": 57474, "2018": 52055}, "Furniture and fixtures": {"Useful Life": 7, "2019": 6096, "2018": 4367}, "Leasehold improvements": {"Useful Life": 2, "2019": 22800, "2018": 9987}, "Renovation in progress": {"Useful Life": "n/a", "2019": 8, "2018": 1984}, "Build-to-suit property": {"Useful Life": 25, "2019": "\u2014", "2018": 51058}, "Total property and equipment, gross": {"Useful Life": "", "2019": 86378, "2018": 119451}, "Less: accumulated depreciation and amortization": {"Useful Life": "", "2019": -49852, "2018": -42197}, "Total property and equipment, net": {"Useful Life": "", "2019": 36526, "2018": 77254}}
leasehold_improvements_2018 = df["Leasehold improvements"]["2018"]
total_property_and_equipment_gross_2018 = df["Total property and equipment, gross"]["2018"]
answer = leasehold_improvements_2018 / total_property_and_equipment_gross_2018 * 100.0