carnet vs laissez-passer

carnet

noun
  • A customs document that allows the temporary duty-free importation of a particular article 

  • An admission pass. 

  • A ticket book, a collection of tickets in the form of a booklet often sold at a discount to single tickets. 

laissez-passer

noun
  • A pass or permit; a document permitting the bearer to travel, sometimes issued as an emergency passport. 

How often have the words carnet and laissez-passer occurred in a corpus of books? (source: Google Ngram Viewer )