What is the percentage increase in revenue by China from 2018 to 2019?
{"United States": {"2019": 70702, "2018": 56839, "2017": 60723}, "China": {"2019": 159637, "2018": 98906, "2017": 148431}, "Germany": {"2019": 57657, "2018": 58711, "2017": 57051}, "Thailand": {"2019": 82413, "2018": 68217, "2017": 48016}, "Other": {"2019": 94254, "2018": 57218, "2017": 70945}, "Total revenue": {"2019": 464663, "2018": 339891, "2017": 385166}}
china_2019 = df["China"]["2019"]
china_2018 = df["China"]["2018"]
answer = ( china_2019 - china_2018 ) / china_2018 * 100.0