firmness vs intransigence

firmness

noun
  • strictness; mental strength 

  • security; steadfastness; good grip 

  • physical durability; rigidness (of material) 

intransigence

noun
  • Unwillingness to change one's views or to agree. 

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