oust vs perpetuate

oust

verb
  • To expel; to remove. 

perpetuate

verb
  • To make (something) perpetual; to make (something) continue for an indefinite time; also, to preserve (something) from extinction or oblivion. 

  • To prolong the existence of (something) by repetition; to reinforce. 

  • To record (the testimony of a witness) which may be lost before a matter comes to trial. 

adj
  • Perpetual, or made perpetual; continued for an indefinite time. 

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