What is the percentage change in the value of vessels between January 1, 2018 and 2019?
{"All figures in USD 000     -- Vessels as of January 1  ": {"2019": 1307087, "2018": 1769967}, "All figures in USD 000     -- Additions Vessels  ": {"2019": 2531, "2018": 169446}, "All figures in USD 000     -- Disposals Vessels  ": {"2019": "-", "2018": -632326}, "All figures in USD 000     -- Drydocking as of January 1  ": {"2019": 52331, "2018": 119303}, "All figures in USD 000     -- Additions Drydocking  ": {"2019": 7618, "2018": 8210}, "All figures in USD 000     -- Disposals Drydocking  ": {"2019": "-", "2018": -75182}, "All figures in USD 000     -- Total Vessels and Drydocking  ": {"2019": 1369567, "2018": 1359418}, "All figures in USD 000     -- Less Accumulated Depreciation  ": {"2019": -469570, "2018": -405660}, "All figures in USD 000     -- Less Accumulated Impairment Loss on Vessels": {"2019": "-", "2018": "-**"}, "All figures in USD 000     -- Vessels  ": {"2019": 899997, "2018": 953758}}
vessels_2019 = df["All figures in USD 000     -- Vessels as of January 1  "]["2019"]
vessels_2018 = df["All figures in USD 000     -- Vessels as of January 1  "]["2018"]
answer = ( vessels_2019 - vessels_2018 ) / vessels_2018 * 100.0