introduce vs proffer

introduce

verb
  • To make (something or someone) known by formal announcement or recommendation. 

  • To cause (someone) to be acquainted (with someone else). 

  • To add (something) to a system, a mixture, or a container. 

  • To bring (something) into practice. 

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. 

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