What is the change in Provision for income taxes from 2018 to 2019?
{"Provision for income taxes": {"2019": 2945.0, "2018": 3584.0, "2019 vs. 2018": -639.0, "": -17.8}, "Effective income tax rate": {"2019": 13.0, "2018": 18.3, "2019 vs. 2018": "", "": ""}}
provision_for_income_taxes_2019 = df["Provision for income taxes"]["2019"]
provision_for_income_taxes_2018 = df["Provision for income taxes"]["2018"]
answer = provision_for_income_taxes_2019 - provision_for_income_taxes_2018