immutability vs strength

immutability

noun
  • The state or quality of being immutable; immutableness. 

  • The state of being unchangeable in the memory after creation. 

strength

noun
  • A positive attribute. 

  • The intensity of a force or power; potency. 

  • The quality or degree of being strong. 

  • The strongest part of something; that on which confidence or reliance is based. 

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