What is the value of the 2019 total voyage revenue as a percentage of the 2018 total voyage revenues?
{"Spot charter revenues*": {"2019": 283007, "2018": 259978, "2017": 257495}, "Time charter revenues  ": {"2019": 34213, "2018": 29038, "2017": 39646}, "Total Voyage Revenues  ": {"2019": 317220, "2018": 289016, "2017": 297141}}
total_voyage_revenue_2019 = df["Total Voyage Revenues  "]["2019"]
total_voyage_revenue_2018 = df["Total Voyage Revenues  "]["2018"]
answer = total_voyage_revenue_2019 / total_voyage_revenue_2018 * 100.0