What is the percentage change in the value of computer software from 2018 to 2019?
{"Development test equipment": {"2019": 16461, "2018": 19110}, "Computer software": {"2019": 76134, "2018": 76134}, "Office equipment": {"2019": 66685, "2018": 61367}, "Office fixtures and furniture": {"2019": 330568, "2018": 330568}, "Leasehold improvements": {"2019": 18016, "2018": 18016}, "Total": {"2019": 507864, "2018": 505195}, "Accumulated depreciation and amortization": {"2019": -321339, "2018": -257906}, "Total property and equipment": {"2019": 186525, "2018": 247289}}
computer_software_2019 = df["Computer software"]["2019"]
computer_software_2018 = df["Computer software"]["2018"]
answer = (computer_software_2019 - computer_software_2018) / computer_software_2018 * 100.0