culmination vs final act

culmination

noun
  • Attainment or arrival at the highest pitch of glory, power, etc. 

  • The attainment of the highest point of altitude reached by a heavenly body; passage across the meridian; transit. 

  • Endpoint (usually good) arrived at after some series of actions or events, or some period , usually after the series or period has ended. The sum of something. 

  • A ceremony marking the completion of studies at an elementary school, middle school or junior high school, the term "graduation" being reserved for high school. 

final act

noun
  • A final performance or accomplishment, before one's retirement or ultimate demise. 

  • The last part of a play, film, or narrative in which the strands of the plot are drawn together and matters are explained. 

How often have the words culmination and final act occurred in a corpus of books? (source: Google Ngram Viewer )