What is the difference between total revenue for fiscal year 2019 and 2018?
{"Revenues: -- Canada": {"2019": 153890, "2018": 149812, "2017": 227115}, "Revenues: -- United States": {"2019": 1490863, "2018": 1425244, "2017": 1090049}, "Revenues: -- United Kingdom": {"2019": 182815, "2018": 201821, "2017": 159817}, "Revenues: -- Germany": {"2019": 203403, "2018": 198253, "2017": 166611}, "Revenues: -- Rest of Europe": {"2019": 534204, "2018": 517693, "2017": 394132}, "Revenues: -- All other countries": {"2019": 303580, "2018": 322418, "2017": 253333}, "Revenues: -- Total revenues": {"2019": 2868755, "2018": 2815241, "2017": 2291057}}
total_revenue_2019 = df["Revenues: -- Total revenues"]["2019"]
total_revenue_2018 = df["Revenues: -- Total revenues"]["2018"]
answer = total_revenue_2019 - total_revenue_2018