constancy vs disequilibrium

constancy

noun
  • The quality of being constant; steadiness or faithfulness in action, affections, purpose, etc. 

  • An unchanging quality or characteristic of a person or thing. 

disequilibrium

noun
  • The loss of equilibrium or stability, especially due to an imbalance of forces. 

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