originate vs retain

originate

verb
  • To cause (someone or something) to be; to bring (someone or something) into existence; to produce or initiate a person or thing. 

  • To come into existence; to have origin or beginning; to spring, be derived (from, with). 

retain

verb
  • 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 keep in possession or use. 

  • To hold secure. 

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