decency vs impropriety

decency

noun
  • That which is proper or becoming. 

  • The quality of being decent; propriety. 

impropriety

noun
  • The condition of being improper. 

  • An improper act. 

  • Improper language. 

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