What was the percentage change in the balance at end of fiscal year between 2018 and 2019?
{"Balance at beginning of fiscal year": {"July 27, 2019": 245, "July 28, 2018": 272, "July 29, 2017": 242}, "Restricted stock, stock units, and other share-based awards granted": {"July 27, 2019": -67, "July 28, 2018": -70, "July 29, 2017": -76}, "Share-based awards canceled/forfeited/expired": {"July 27, 2019": 18, "July 28, 2018": 18, "July 29, 2017": 78}, "Shares withheld for taxes and not issued": {"July 27, 2019": 23, "July 28, 2018": 25, "July 29, 2017": 28}, "Other": {"July 27, 2019": 1, "July 28, 2018": "\u2014", "July 29, 2017": "\u2014"}, "Balance at end of fiscal year": {"July 27, 2019": 220, "July 28, 2018": 245, "July 29, 2017": 272}}
balance_2019 = df["Balance at end of fiscal year"]["July 27, 2019"]
balance_2018 = df["Balance at beginning of fiscal year"]["July 27, 2019"]
answer = (balance_2019 - balance_2018) / balance_2018 * 100.0