plinth vs subfloor

plinth

noun
  • A base or pedestal beneath a cabinet. 

  • A block or slab upon which a column, pedestal, statue or other structure is based. 

  • The bottom course of stones or bricks supporting a wall. 

subfloor

noun
  • The floor structure supporting and underlying the visible flooring or other finishing surface such as a carpet 

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