by a long shot vs by a long way

by a long shot

prep
  • By a wide margin; indicates a very big difference or disparity. 

by a long way

prep
  • To a considerably large extent, easily. Typically used in the negative to indicate something far removed and not easily altered. 

How often have the words by a long shot and by a long way occurred in a corpus of books? (source: Google Ngram Viewer )