leak out vs make known

leak out

verb
  • To be revealed (especially, of information intended to be kept secret). 

  • To spill or pour out, because of a leak. 

make known

verb
  • To disclose (a secret). 

  • To announce (some information) generally. 

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