legitimacy vs well-foundedness

legitimacy

noun
  • The quality or state of being legitimate or valid; validity. 

  • Lawfulness of birth or origin; directness of descent as affecting the royal succession. 

well-foundedness

noun
  • The state or quality of being well-founded. 

How often have the words legitimacy and well-foundedness occurred in a corpus of books? (source: Google Ngram Viewer )