doggedness vs firmness

doggedness

noun
  • The state of being dogged; persistence; perseverance; tenacity; stubbornness. 

firmness

noun
  • strictness; mental strength 

  • security; steadfastness; good grip 

  • physical durability; rigidness (of material) 

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