concubine vs hooker

concubine

noun
  • A slave-girl or woman, kept for instance in a harem, who is held for sexual service. 

  • A sexual partner, especially a woman, to whom one is not or cannot be married. 

  • A woman who lives with a man, but who is not a wife. 

hooker

noun
  • A prostitute. 

  • One who, or that which, hooks. 

  • A batsman or batswoman adept at or fond of playing hook shots. 

  • A crocheter. 

  • Any antiquated craft. 

  • A player who hooks the ball out of the scrum with his foot. 

  • A small fishing boat. 

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