frugality vs severity

frugality

noun
  • A sparing use; sparingness. 

  • The quality of being frugal; prudent economy; thrift. 

severity

noun
  • The degree of something undesirable; badness or seriousness. 

  • The state of being severe. 

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