immutability vs solidity

immutability

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

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

solidity

noun
  • The state or quality of being solid. 

  • Moral firmness; validity; truth; certainty. 

  • The solid contents of a body; volume; amount of enclosed space. 

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