gentrification vs refitting

gentrification

noun
  • The renewal and rebuilding that accompanies the influx of middle class or affluent people into deteriorating areas and often displaces earlier, usually poorer, residents; any example of such a process. 

refitting

noun
  • The act by which something is refitted; a refit. 

How often have the words gentrification and refitting occurred in a corpus of books? (source: Google Ngram Viewer )