Rolls-Royce vs greatest thing since sliced bread

Rolls-Royce

noun
  • A car made by this manufacturer. 

  • Anything that is the best of its type; the best quality product possible. 

name
  • any of several British companies that make motor cars, aero engines, etc. 

greatest thing since sliced bread

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

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