concealment vs demonstration

concealment

noun
  • The practice of keeping secrets. 

  • protection from observation or surveillance. 

  • The condition of being hidden or concealed. 

demonstration

noun
  • A public display of group opinion, such as a protest march. 

  • A proof. 

  • Expression of one's feelings by outward signs. 

  • The act of demonstrating; showing or explaining something. 

  • A prisoner's act of beating up another prisoner. 

  • An event at which something will be demonstrated. 

  • A show of military force. 

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