rodman vs troller

rodman

noun
  • The person who holds the surveying rod for a surveyor 

troller

noun
  • One who fishes by trolling. 

  • An engine-powered fishing boat, used for moving slowly while fishing lines drag behind, sometimes able to sail in shallow water. 

  • A troll; a user who maliciously provokes others. 

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