groundskeeping vs tillage

groundskeeping

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

tillage

noun
  • Land cultivated in this way. 

  • The cultivation of arable land by plowing, sowing and raising crops. 

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