What is the value of the subscription costs as a percentage of the total cost of revenue in 2019?
{"Cost of revenues -- Subscriptions": {"2019": 160320, "2017": 89193}, "Cost of revenues -- Other": {"2019": 70723, "2017": 32078}, "Cost of revenues -- Total cost of revenues": {"2019": 231043, "2017": 121271}, "Percentage of revenues -- Subscriptions": {"2019": 18, "2017": 18}, "Percentage of revenues -- Other": {"2019": 8, "2017": 6}, "Gross margins -- Subscriptions": {"2019": 80, "2017": 81}, "Gross margins -- Other": {"2019": 17, "2017": 16}, "Gross margins -- Total gross margin %": {"2019": 74, "2017": 76}}
cost_of_revenues_subscriptions_2019 = df["Cost of revenues -- Subscriptions"]["2019"]
cost_of_revenues_total_cost_of_revenues_2019 = df["Cost of revenues -- Total cost of revenues"]["2019"]
answer = cost_of_revenues_subscriptions_2019 / cost_of_revenues_total_cost_of_revenues_2019 * 100.0