austereness vs unpretentiousness

austereness

noun
  • harshness or astringent sourness to the taste; acerbity. 

  • severity; strictness; austerity. 

unpretentiousness

noun
  • The state or condition of being unpretentious. 

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