put lipstick on a pig vs window-dress

put lipstick on a pig

verb
  • To superficially alter something in the hope of making it seem more appealing than it is in actuality. 

window-dress

verb
  • To give something superficial attractiveness 

  • To decorate the window of a shop 

How often have the words put lipstick on a pig and window-dress occurred in a corpus of books? (source: Google Ngram Viewer )