What is the percentage change in Deferred revenue between 2018 and 2019?
{"Deferred tax assets: -- Accrued expenses": {"2019": 2427, "2018": 2353}, "Deferred tax assets: -- Long-lived intangible assets and fixed assets - basis difference": {"2019": 25178, "2018": 22947}, "Deferred tax assets: -- Net operating loss carryforwards": {"2019": 81575, "2018": 82017}, "Deferred tax assets: -- Stock-based compensation": {"2019": 15398, "2018": 15172}, "Deferred tax assets: -- Operating lease liabilities": {"2019": 17281, "2018": "\u2014"}, "Deferred tax assets: -- Deferred revenue": {"2019": 3258, "2018": 2861}, "Deferred tax assets: -- Other": {"2019": 5100, "2018": 4557}, "Deferred tax assets: -- Total deferred tax assets": {"2019": 150217, "2018": 129907}, "Deferred tax assets: -- Valuation allowance": {"2019": -116915, "2018": -117058}, "Deferred tax assets: -- Deferred tax assets, net of valuation allowance": {"2019": 33302, "2018": 12849}, "Deferred tax liabilities: -- Prepaid expenses and deferred commissions": {"2019": -14502, "2018": -10831}, "Deferred tax liabilities: -- Operating right-of-use assets": {"2019": -16960, "2018": "\u2014"}, "Deferred tax liabilities: -- Other": {"2019": -795, "2018": -976}, "Deferred tax liabilities: -- Total deferred tax liabilities": {"2019": -32257, "2018": -11807}, "Deferred tax liabilities: -- Net deferred tax assets": {"2019": 1045, "2018": 1042}}
deferred_revenue_2019 = df["Deferred tax assets: -- Deferred revenue"]["2019"]
deferred_revenue_2018 = df["Deferred tax assets: -- Deferred revenue"]["2018"]
answer = (deferred_revenue_2019 - deferred_revenue_2018) / deferred_revenue_2018 * 100.0