What is the percentage change in cash?
{"": {"2019": "", "2018": "(in thousands)"}, "Cash": {"2019": 347, "2018": 374}, "Restricted cash": {"2019": 9967, "2018": 10000}, "Other current assets": {"2019": 33, "2018": "\u2014"}, "Long-term capitalized contract costs": {"2019": "\u2014", "2018": 33818}, "Long-term contracts financing receivable": {"2019": 115508, "2018": "\u2014"}, "Other noncurrent assets": {"2019": 1419, "2018": 810}, "Total assets": {"2019": 127274, "2018": 45002}, "Trade accounts payable": {"2019": 25, "2018": 165}, "Accrued compensation and other current liabilities": {"2019": 191, "2018": "\u2014"}, "Due to Cubic": {"2019": 25143, "2018": 11724}, "Other long-term liabilities": {"2019": 21605, "2018": 13}, "Long-term debt": {"2019": 61994, "2018": 9056}, "Total liabilities": {"2019": 108958, "2018": 20958}, "Total Cubic equity": {"2019": -603, "2018": -304}, "Noncontrolling interests": {"2019": 18919, "2018": 24348}, "Total liabilities and owners' equity": {"2019": 127274, "2018": 45002}}
cash_2019 = df["Cash"]["2019"]
cash_2018 = df["Cash"]["2018"]
answer = ( cash_2019 - cash_2018 ) / cash_2018 * 100.0