unblock vs uncover

unblock

verb
  • To remove or clear a block or obstruction from. 

  • In whist, to throw away a high card so as not to interrupt one's partner's long suit. 

  • To free or make available. 

  • To enable communication again, via telephone, instant messaging, etc., with (somebody previously blocked). 

noun
  • The removal of a block or blockage. 

uncover

verb
  • To remove a cover from. 

  • To remove one's hat or cap as a mark of respect. 

  • To reveal the identity of. 

  • To expose the genitalia. 

  • To show openly; to disclose; to reveal. 

  • To expose (lines of formation of troops) successively by the wheeling to right or left of the lines in front. 

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