immutability vs permanence

immutability

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

  • The state or quality of being immutable; immutableness. 

permanence

noun
  • The state of being permanent. 

  • The reciprocal of magnetic inductance. 

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