mutt's nuts vs the bee's knees

mutt's nuts

noun
  • Something regarded as outstandingly good. 

the bee's knees

noun
  • Something or someone excellent, surpassingly wonderful, or cool. 

  • Used other than figuratively or idiomatically: see bee, -'s, knee. Corbiculae. 

How often have the words mutt's nuts and the bee's knees occurred in a corpus of books? (source: Google Ngram Viewer )