boating vs pilotage

boating

noun
  • The activity of going out onto a body of water in a boat. 

  • In Persia, a punishment of capital offenders, by laying them on the back in a covered boat, where they are left to perish. 

pilotage

noun
  • The use of landmarks to guide a vessel or aircraft to its destination. 

  • The occupation of a pilot. 

  • The fee paid to a pilot. 

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