constancy vs dirty work

constancy

noun
  • The quality of being constant; steadiness or faithfulness in action, affections, purpose, etc. 

  • An unchanging quality or characteristic of a person or thing. 

dirty work

noun
  • One or more unpleasant tasks, assignments, or employment duties, especially those of a disreputable or illicit nature. 

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