a perfect example of its kind vs the bee's knees

a perfect example of its kind

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 a perfect example of its kind and the bee's knees occurred in a corpus of books? (source: Google Ngram Viewer )