binder clip vs scrap paper

binder clip

noun
  • A simple device for binding a few to many sheets of paper, leaving the sheets intact; a strip of spring steel bent into the shape of an isosceles triangle with loops at the apex. 

scrap paper

noun
  • scratch paper 

  • Used paper, to be reused for jotting notes etc. 

How often have the words binder clip and scrap paper occurred in a corpus of books? (source: Google Ngram Viewer )