groundskeeping vs refinement

groundskeeping

noun
  • The activity of tending an area of land for aesthetic or functional purposes; typically as an employee of a person or institution 

refinement

noun
  • High-class style; cultivation. 

  • The act, or the result of refining; the removal of impurities, or a purified material 

  • A fine or subtle distinction. 

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