announce vs disseminate

announce

verb
  • to give public notice, especially for the first time; to make known 

  • to pronounce; to declare by judicial sentence 

disseminate

verb
  • To sow and scatter principles, ideas, opinions, etc, or concrete things, for growth and propagation, like seeds. 

  • To become widespread. 

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