fossil fuel vs kerosene

fossil fuel

noun
  • Any fuel derived from hydrocarbon deposits such as coal, petroleum, natural gas and, to some extent, peat; these fuels are non-renewable, and their burning moves carbon from underground into the atmosphere via the greenhouse gas carbon dioxide. 

kerosene

noun
  • A thin colorless to straw-colored petroleum-based fuel heavier than gasoline/petrol or naptha but lighter than diesel, used primarily as jet fuel but also for heating and lighting in some remote or impoverished areas. 

How often have the words fossil fuel and kerosene occurred in a corpus of books? (source: Google Ngram Viewer )