conceal vs unearth

conceal

verb
  • To hide something from view or from public knowledge, to try to keep something secret. 

unearth

verb
  • To uncover or find; to bring out from concealment 

  • To drive or draw from the earth. 

  • To dig up. 

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