What is the change in the value of land between 2018 and 2019?
{"Land": {"2019": 1565, "2018": 1747}, "Buildings and improvements": {"2019": 17332, "2018": 17520}, "Machinery and equipment": {"2019": 30670, "2018": 29692}, "Vehicles": {"2019": 778, "2018": 937}, "Office equipment": {"2019": 851, "2018": 838}, "Construction in process": {"2019": 362, "2018": 546}, "": {"2019": 51558, "2018": 51280}, "Less accumulated depreciation": {"2019": -29284, "2018": -26707}, "Total property, plant and equipment, net": {"2019": 22274, "2018": 24573}}
land_2019 = df["Land"]["2019"]
land_2018 = df["Land"]["2018"]
answer = land_2019 - land_2018