assertion vs pronouncement

assertion

noun
  • Something which is asserted; a declaration; a statement asserted. 

  • A statement in a program asserting a condition expected to be true at a particular point, used in debugging. 

  • A statement or declaration which lacks support or evidence. 

  • The act of asserting; positive declaration or averment. 

  • Maintenance; vindication 

pronouncement

noun
  • An utterance. 

  • An official public announcement. 

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