What was the percentage change in net revenue from 2017 to 2019?
{"": {"2019": "", "2018": "(in thousands, except percentage data)", "2017": ""}, "Net revenue": {"2019": 711391, "2018": 771060, "2017": 768261}, "Percentage of net revenue": {"2019": 71.2, "2018": 72.8, "2017": 73.9}, "Contribution income": {"2019": 67775, "2018": 96340, "2017": 83870}, "Contribution margin": {"2019": 9.5, "2018": 12.5, "2017": 10.9}}
net_revenue_2019 = df["Net revenue"]["2019"]
net_revenue_2017 = df["Net revenue"]["2017"]
answer = (net_revenue_2019 - net_revenue_2017) / net_revenue_2017 * 100.0