What was the change in the adjusted operating profit in 2019 from 2018?
{"": {"2019": "\u00a3m", "2018": "\u00a3m"}, "Property, plant and equipment": {"2019": 251.2, "2018": 230.8}, "Right-of-use assets (IFRS 16)": {"2019": 40.8, "2018": "\u2013"}, "Prepayments": {"2019": 0.9, "2018": 6.2}, "Inventories": {"2019": 185.9, "2018": 160.6}, "Trade receivables": {"2019": 240.7, "2018": 245.1}, "Other current assets": {"2019": 35.3, "2018": 32.9}, "Tax recoverable": {"2019": 8.4, "2018": 4.6}, "Trade, other payables and current provisions": {"2019": -178.3, "2018": -172.0}, "Current tax payable": {"2019": -26.7, "2018": -23.7}, "Capital employed": {"2019": 558.2, "2018": 484.5}, "Average capital employed": {"2019": 521.4, "2018": 482.2}, "Average capital employed (excluding IFRS 16)": {"2019": 501.0, "2018": 482.2}, "Operating profit": {"2019": 245.0, "2018": 299.1}, "Adjustments (see adjusted operating profit on page 160)": {"2019": 37.7, "2018": -34.2}, "Adjusted operating profit": {"2019": 282.7, "2018": 264.9}, "Adjusted operating profit (excluding IFRS 16)": {"2019": 281.4, "2018": 264.9}, "Return on capital employed": {"2019": 54.2, "2018": 54.9}, "Return on capital employed (excluding IFRS 16)": {"2019": 56.2, "2018": 54.9}}
adjusted_operating_profit_2019 = df["Adjusted operating profit"]["2019"]
adjusted_operating_profit_2018 = df["Adjusted operating profit"]["2018"]
answer = adjusted_operating_profit_2019 - adjusted_operating_profit_2018