What was the percentage change in interest income between 2018 and 2019?
{"Interest expense": {"2019": -2648, "2018": -2085}, "Interest income": {"2019": 1737, "2018": 1826}, "Other (expense) income": {"2019": -2638, "2018": -2676}, "Total other (expense) income, net": {"2019": -3549, "2018": -2935}}
interest_income_2019 = df["Interest income"]["2019"]
interest_income_2018 = df["Interest income"]["2018"]
answer = ( interest_income_2019 - interest_income_2018 ) / interest_income_2018 * 100.0