proffer vs propose marriage

proffer

verb
  • To offer for acceptance; to propose to give; to make a tender of. 

noun
  • An offer made; something proposed for acceptance by another; a tender. 

propose marriage

verb
  • To ask someone if they want to become one's spouse. 

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