sketchbook vs treasury

sketchbook

noun
  • A book of printed sketches. 

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

treasury

noun
  • A collection of artistic or literary works. 

  • A place where state or royal money and valuables are stored. 

  • A place where treasure is stored safely. 

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