irrigate vs percolate

irrigate

verb
  • To clean (a wound) with a fluid. 

  • To supply (farmland) with water, by building ditches, pipes, etc. 

percolate

verb
  • To drain or seep through a porous substance. 

  • To pass a liquid through a porous substance; to filter. 

  • To make (coffee) in a percolator. 

  • To spread slowly or gradually; to slowly become noticed or realised. 

noun
  • A liquid that has been percolated. 

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