properness vs propriety

properness

noun
  • The state or condition of being proper; propriety. 

  • The state or condition of being proper (of a proper fraction, proper subset, etc.). 

propriety

noun
  • Correctness in behaviour and morals; good manners, seemliness. 

  • The fact of possessing something; ownership. 

  • Suitability, fitness; the quality of being appropriate. 

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