oil burner vs subcompact

oil burner

noun
  • A heating device which burns fuel oil; an oil furnace. 

  • A machine that uses oil as its fuel. 

  • A device whose operation causes apparent combustion of lubricating oil. 

subcompact

noun
  • Something that is smaller than the compact version, especially a very small car. 

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