cahier vs writing pad

cahier

noun
  • A number of sheets of paper put loosely together; especially one of the successive portions of a work printed in numbers. 

  • A memorial of a body; a report of legislative proceedings, etc. 

writing pad

noun
  • A collection of blank pages of writing paper, bound together, often with a cardboard cover 

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