instability vs steadfastness

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. 

steadfastness

noun
  • Loyalty in the face of trouble and difficulty. 

  • Steadfast resolution. 

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