What percentage of total operating expenses was General and administrative in 2019?
{"Operating expenses:                 -- Research and development": {"2019": 57939, "2018": 38373, "Amount  ": 19566, "% Change": 51}, "Operating expenses:                 -- Sales and marketing": {"2019": 139194, "2018": 121246, "Amount  ": 17948, "% Change": 15}, "Operating expenses:                 -- General and administrative": {"2019": 53759, "2018": 36989, "Amount  ": 16770, "% Change": 45}, "Operating expenses:                 -- Impairment of long-lived assets  ": {"2019": "\u2014", "2018": 1712, "Amount  ": -1712, "% Change": "nm "}, "Operating expenses:                 -- Restructuring  ": {"2019": -170, "2018": 832, "Amount  ": -1002, "% Change": "nm "}, "Operating expenses:                 -- Total operating expenses": {"2019": 250722, "2018": 199152, "Amount  ": 51570, "% Change": 26}}
general_admin_2019 = df["Operating expenses:                 -- General and administrative"]["2019"]
total_expenses_2019 = df["Operating expenses:                 -- Total operating expenses"]["2019"]
answer = general_admin_2019 / total_expenses_2019 * 100.0