harbinger vs prognostication

harbinger

noun
  • A person or thing that foreshadows or foretells the coming of someone or something. 

verb
  • To announce or precede; to be a harbinger of. 

prognostication

noun
  • A statement about or prior knowledge of the future. 

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