dustheap vs landfill

dustheap

noun
  • A pile of rubbish. 

landfill

noun
  • The material so disposed of. 

  • A site at which refuse is buried under layers of earth. 

verb
  • To dispose of (garbage) by burying it at a landfill site. 

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