asceticism vs self-abnegation

asceticism

noun
  • The principles and practices of an ascetic; extreme self-denial and austerity. 

self-abnegation

noun
  • An act of self-denial. 

  • The denial or invalidation of one's own needs, interests, etc. for the sake of another's; the setting aside of self-interest. 

How often have the words asceticism and self-abnegation occurred in a corpus of books? (source: Google Ngram Viewer )