ferret out vs fossick

ferret out

verb
  • To discover something after searching. 

fossick

verb
  • To search for something; to rummage. 

  • To search for gems, gold, etc., on the surface or in abandoned workings. 

  • To be troublesome. 

  • To elicit information; to ferret out. 

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