endurance vs instability

endurance

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

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

  • Ability to endure hardship. 

instability

noun
  • The quality of being unstable. 

  • A state that is not in equilibrium, or in which a small change has a large irreversible effect. 

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