gentry vs the upper middle class

gentry

noun
  • People of education and good breeding. 

  • Courtesy; civility; complaisance. 

  • In a restricted sense, those people between the nobility and the yeomanry. 

  • Birth; condition; rank by birth. 

the upper middle class

How often have the words gentry and the upper middle class occurred in a corpus of books? (source: Google Ngram Viewer )