canvassing vs polling

canvassing

noun
  • The act of one who canvasses or solicits. 

polling

noun
  • A technique that continually interrogates a peripheral or service to see if it has data to transfer. 

  • the process of voting in an election. 

  • The action of taking a poll. 

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