What was the change in operating profit between 2018 and 2019?
{"Total revenue": {"2019": 529646, "2018": 414673}, "Total costs and expenses": {"2019": 408693, "2018": 261883}, "Operating profit": {"2019": 120953, "2018": 152790}, "Total other income (expense), net": {"2019": -22297, "2018": -19276}, "Net income": {"2019": 98656, "2018": 133514}}
operating_profit_2019 = df["Operating profit"]["2019"]
operating_profit_2018 = df["Operating profit"]["2018"]
answer = operating_profit_2019 - operating_profit_2018