make known vs unveil

make known

verb
  • To disclose (a secret). 

  • To announce (some information) generally. 

unveil

verb
  • To remove a veil from; to uncover; to reveal something hidden. 

  • To remove a veil; to reveal oneself. 

  • to show, especially for the first time 

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