dissolution vs disunion

dissolution

noun
  • The termination of an organized body or legislative assembly, especially a formal dismissal. 

  • The quality of being dissolute. 

  • Dissolving, or going into solution. 

  • Disintegration, or decomposition into fragments. 

disunion

noun
  • separation of a union 

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