piece of cake vs pleasure cruise

piece of cake

noun
  • A job, task or other activity that is pleasant – or, by extension, easy or simple. 

  • Used other than figuratively or idiomatically: see piece, cake. 

pleasure cruise

noun
  • A pleasant or easy situation without any challenges. 

  • A pleasure trip, especially on a ship. 

How often have the words piece of cake and pleasure cruise occurred in a corpus of books? (source: Google Ngram Viewer )