perpetuate vs shorten

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. 

shorten

verb
  • To reduce or diminish in amount, quantity, or extent; to lessen. 

  • To take in the slack of (a rope). 

  • To reduce (sail) by taking it in. 

  • To become shorter. 

  • To make shorter; to abbreviate. 

  • To make short or friable, as pastry, with butter, lard, etc. 

  • To make deficient (as to); to deprive (of). 

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