propriety vs suitability

propriety

noun
  • Suitability, fitness; the quality of being appropriate. 

  • The fact of possessing something; ownership. 

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

suitability

noun
  • The quality of being suitable. 

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