What was the percentage change between accounts payable in 2018 and 2019?
{"Accounts payable": {"December 31, 2019": 32878, "December 31, 2018": 20214}, "Accrued expenses": {"December 31, 2019": 10092, "December 31, 2018": 34557}, "Subsidiary unit awards": {"December 31, 2019": 141, "December 31, 2018": 200}, "Other current liabilities": {"December 31, 2019": 5616, "December 31, 2018": 3459}, "Accounts payable, accrued expenses and other current liabilities": {"December 31, 2019": 48727, "December 31, 2018": 58430}}
accounts_payable_2019 = df["Accounts payable"]["December 31, 2019"]
accounts_payable_2018 = df["Accounts payable"]["December 31, 2018"]
answer = (accounts_payable_2019 - accounts_payable_2018) / accounts_payable_2018 * 100.0