fuel vs red rag to a bull

fuel

noun
  • Something that stimulates, encourages or maintains an action. 

  • Substance that provides nourishment for a living organism; food. 

  • Substance consumed to provide energy through combustion, or through chemical or nuclear reaction. 

verb
  • To exacerbate, to cause to grow or become greater. 

  • To provide with fuel. 

red rag to a bull

noun
  • Something that will enrage another particular person. 

How often have the words fuel and red rag to a bull occurred in a corpus of books? (source: Google Ngram Viewer )