What was the percentage change in revenue from 2018 to 2019?
{"(EUR thousand)": {"2018": "Revenue", "2019": "Revenue"}, "United States": {"2018": 175855, "2019": 339463}, "Europe": {"2018": 165602, "2019": 126203}, "Asia": {"2018": 476624, "2019": 818194}, "Total": {"2018": 818081, "2019": 1283860}}
total_2019 = df["Total"]["2019"]
total_2018 = df["Total"]["2018"]
answer = ( total_2019 - total_2018 ) / total_2018 * 100.0