chef vs sous chef

chef

verb
  • To stab with a knife, to shank. 

  • To work as a chef; to prepare and cook food professionally. 

noun
  • The presiding cook in the kitchen of a large household. 

  • A reliquary in the shape of a head. 

  • Any cook. 

  • The head cook of a restaurant or other establishment. 

  • One who manufactures illegal drugs; a cook. 

sous chef

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