What is the change in income from operations between 2018 and 2019?
{"Year Ended December 31, -- ": {"2019": 2019, "2018": 2018}, "(In thousands) -- Revenues": {"2019": 36898, "2018": 36149}, "(In thousands) -- Income from operations": {"2019": 4461, "2018": 4973}, "(In thousands) -- Income from operations as a % of revenues": {"2019": 12, "2018": 14}}
income_from_operations_2019 = df["(In thousands) -- Income from operations"]["2019"]
income_from_operations_2018 = df["(In thousands) -- Income from operations"]["2018"]
answer = income_from_operations_2019 - income_from_operations_2018