endurance vs prolongation

endurance

noun
  • The measure of a person's stamina or persistence. 

  • The length of time that a ship's rations will supply 

  • Ability to endure hardship. 

prolongation

noun
  • The act of prolonging. 

  • That which has been prolonged; an extension. 

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