lithograph vs sketchbook

lithograph

noun
  • A printed image produced by lithography. 

verb
  • To create a copy of an image through lithography. 

sketchbook

noun
  • A book of printed sketches. 

  • A book or pad with blank pages for sketching; a sketch pad. 

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