mystery tour vs peregrination

mystery tour

noun
  • A short-duration outing by coach to a destination that is not revealed in advance 

peregrination

noun
  • A journey or trip, especially by foot; also (uncountable) journeying, travelling. 

  • Straying from the main subject in speech or writing; digression; (countable) an instance of this. 

  • Broad or systematic discussion of a subject; (countable) an instance of this; a discourse. 

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