What was the percentage change in cash and cash equivalents between 2018 and 2019?
{"Cash and cash equivalents": {"April 26, 2019": 2325, "April 27, 2018": 2941}, "Short-term investments": {"April 26, 2019": 1574, "April 27, 2018": 2450}, "Total": {"April 26, 2019": 3899, "April 27, 2018": 5391}}
cash_2019 = df["Cash and cash equivalents"]["April 26, 2019"]
cash_2018 = df["Cash and cash equivalents"]["April 27, 2018"]
answer = (cash_2019 - cash_2018) / cash_2018 * 100.0