junket vs mystery tour

junket

noun
  • A pleasure-trip; a journey made for feasting or enjoyment, now especially a trip made ostensibly for business but which entails merrymaking or entertainment. 

  • A type of cream cheese, originally made in a rush basket; later, a food made of sweetened curds or rennet. 

  • A press junket. 

  • A gaming room for which the capacity and limits change daily, often rented out to private vendors who run tour groups through them and give a portion of the proceeds to the main casino. 

  • A feast or banquet. 

verb
  • To go on a junket; to travel. 

  • To regale or entertain with a feast. 

mystery tour

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

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