landfill vs rubbish dump

landfill

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

  • The material so disposed of. 

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

rubbish dump

noun
  • A landfill 

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