What was the percentage change in the  Net cash provided by operating activities  between 2017 and 2018?
{"Revenue": {"July 27, 2019 (1)(2)": 51904.0, "July 28, 2018 (1)(3)": 49330.0, "July 29, 2017": 48005.0, "July 30, 2016 (4)(5)": 49247.0, "July 25, 2015 (4)": 49161.0}, "Net income": {"July 27, 2019 (1)(2)": 11621.0, "July 28, 2018 (1)(3)": 110.0, "July 29, 2017": 9609.0, "July 30, 2016 (4)(5)": 10739.0, "July 25, 2015 (4)": 8981.0}, "Net income per sharebasic": {"July 27, 2019 (1)(2)": 2.63, "July 28, 2018 (1)(3)": 0.02, "July 29, 2017": 1.92, "July 30, 2016 (4)(5)": 2.13, "July 25, 2015 (4)": 1.76}, "Net income per sharediluted": {"July 27, 2019 (1)(2)": 2.61, "July 28, 2018 (1)(3)": 0.02, "July 29, 2017": 1.9, "July 30, 2016 (4)(5)": 2.11, "July 25, 2015 (4)": 1.75}, "Shares used in per-share calculationbasic": {"July 27, 2019 (1)(2)": 4419.0, "July 28, 2018 (1)(3)": 4837.0, "July 29, 2017": 5010.0, "July 30, 2016 (4)(5)": 5053.0, "July 25, 2015 (4)": 5104.0}, "Shares used in per-share calculationdiluted": {"July 27, 2019 (1)(2)": 4453.0, "July 28, 2018 (1)(3)": 4881.0, "July 29, 2017": 5049.0, "July 30, 2016 (4)(5)": 5088.0, "July 25, 2015 (4)": 5146.0}, "Cash dividends declared per common share": {"July 27, 2019 (1)(2)": 1.36, "July 28, 2018 (1)(3)": 1.24, "July 29, 2017": 1.1, "July 30, 2016 (4)(5)": 0.94, "July 25, 2015 (4)": 0.8}, "Net cash provided by operating activities": {"July 27, 2019 (1)(2)": 15831.0, "July 28, 2018 (1)(3)": 13666.0, "July 29, 2017": 13876.0, "July 30, 2016 (4)(5)": 13570.0, "July 25, 2015 (4)": 12552.0}}
net_cash_2018 = df["Net cash provided by operating activities"]["July 28, 2018 (1)(3)"]
net_cash_2017 = df["Net cash provided by operating activities"]["July 29, 2017"]
answer = ( net_cash_2018 - net_cash_2017 ) / net_cash_2017 * 100.0