evacuate vs retain

evacuate

verb
  • To leave or withdraw from; to quit; to retire from 

  • To remove; to eject; to void; to discharge, as the contents of a vessel, or of the bowels. 

  • To cause (or help) to leave or withdraw from. 

  • To make empty; to empty out; to remove the contents of, including to create a vacuum. 

  • To make empty; to deprive. 

  • To make void; to nullify; to vacate. 

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 evacuate and retain occurred in a corpus of books? (source: Google Ngram Viewer )