cliffhanger vs sixty-four dollar question

cliffhanger

noun
  • An ending or stopping point calculated to leave a story unresolved, in order to create suspense. 

  • An outcome which is awaited with keen anticipation, especially one which is delayed for a period of time or which is not known until the last minute. 

sixty-four dollar question

How often have the words cliffhanger and sixty-four dollar question occurred in a corpus of books? (source: Google Ngram Viewer )