moniker vs nom de clavier

moniker

noun
  • A personal name or nickname; an informal label, often drawing attention to a particular attribute. 

  • A person's signature. 

  • An object (structured item of data) used to associate the name of an object with its location. 

nom de clavier

noun
  • A pseudonym used in online communications; a handle. 

How often have the words moniker and nom de clavier occurred in a corpus of books? (source: Google Ngram Viewer )