What was the 2018 profit margin?
{"Revenues": {"2019": 377289, "2018": 312694}, "Cost of revenues": {"2019": -209756, "2018": -170574}, "Gross profit": {"2019": 167533, "2018": 142120}, "Interest income": {"2019": 6314, "2018": 4569}, "Other gains, net": {"2019": 19689, "2018": 16714}, "Selling and marketing expenses": {"2019": -21396, "2018": -24233}, "General and administrative expenses": {"2019": -53446, "2018": -41522}, "Operating profit": {"2019": 118694, "2018": 97648}, "Finance costs, net": {"2019": -7613, "2018": -4669}, "Share of (loss)/profit of associates and joint ventures": {"2019": -1681, "2018": 1487}, "Profit before income tax": {"2019": 109400, "2018": 94466}, "Income tax expense": {"2019": -13512, "2018": -14482}, "Profit for the year": {"2019": 95888, "2018": 79984}, "Attributable to: -- Equity holders of the Company": {"2019": 93310, "2018": 78719}, "Attributable to: -- Non-controlling interests": {"2019": 2578, "2018": 1265}, "Attributable to: -- ": {"2019": 95888, "2018": 79984}, "Attributable to: -- Non-IFRS profit attributable to equity holders of the Company": {"2019": 94351, "2018": 77469}}
profit_2018 = df["Profit for the year"]["2018"]
revenue_2018 = df["Revenues"]["2018"]
answer = profit_2018 / revenue_2018 * 100.0