cooking oil vs margarine

cooking oil

noun
  • A purified fat taken from plant material that is commonly used in cooking, e.g. olive oil, canola oil, sunflower oil, etc. 

margarine

noun
  • A spread, manufactured from a blend of vegetable oils (some of which are hydrogenated), emulsifiers etc, mostly used as a substitute for butter. 

How often have the words cooking oil and margarine occurred in a corpus of books? (source: Google Ngram Viewer )