dumping ground vs junkyard

dumping ground

noun
  • A landfill. 

  • Any place where unwanted items are sent. 

  • A presumably polyphyletic supraspecific taxon where species of unclear affinities are placed. 

junkyard

noun
  • A place where rubbish is placed. 

  • A business that sells used metal or items. 

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