cross one's fingers vs hope for the best

cross one's fingers

verb
  • when telling a lie (and attempting to escape the moral and other consequence of that lie). 

  • To put the middle finger across the index finger, especially 

  • when wishing for luck, or 

hope for the best

How often have the words cross one's fingers and hope for the best occurred in a corpus of books? (source: Google Ngram Viewer )