What is the percentage change in the net value of property and equipment between 2018 and 2019?
{"As of December 31, -- ": {"2019": 2019, "2018": 2018}, "As of December 31, -- Computers, software, furniture and fixtures": {"2019": 1406, "2018": 1407}, "As of December 31, -- Equipment under capital lease  3,348": {"2019": 3348, "2018": 3525}, "As of December 31, -- Less accumulated depreciation and amortization": {"2019": -3171, "2018": -2448}, "As of December 31, -- Property and equipment, net": {"2019": 1583, "2018": 2484}}
net_value_2019 = df["As of December 31, -- Property and equipment, net"]["2019"]
net_value_2018 = df["As of December 31, -- Property and equipment, net"]["2018"]
answer = ( net_value_2019 - net_value_2018 ) / net_value_2018 * 100.0