deal in vs retain

deal in

verb
  • To have an interest in something. 

  • To trade (buy and sell) a named commodity. 

  • To accept (something or a piece of information) as a basis for a decision. 

  • To deal cards to someone entering a game; to enter someone into a game by dealing cards to that person. 

retain

verb
  • To keep in possession or use. 

  • To employ by paying a retainer. 

  • To hold back (a pupil) instead of allowing them to advance to the next class or year. 

  • To keep in one's pay or service. 

  • To hold secure. 

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