greatest thing since sliced bread vs the bee's knees

greatest thing since sliced bread

noun
  • Something amazing, outstanding or praiseworthy, especially a relatively recent invention likely to improve people's lives. 

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 greatest thing since sliced bread and the bee's knees occurred in a corpus of books? (source: Google Ngram Viewer )