greatest thing since sliced bread vs ne plus ultra

greatest thing since sliced bread

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

ne plus ultra

noun
  • The perfect or most extreme example of its kind; the ultimate. 

  • A prohibition against proceeding further; an insuperable obstacle or limiting condition. 

  • The highest, ultimate point of achievement which can be reached; perfection. 

How often have the words greatest thing since sliced bread and ne plus ultra occurred in a corpus of books? (source: Google Ngram Viewer )