copilot vs jockey

copilot

noun
  • A backup or assistant pilot of an aircraft. 

verb
  • To serve as relief or assistant pilot. 

jockey

noun
  • An operator of some machinery or apparatus. 

  • A rapist. 

  • One who rides racehorses competitively. 

  • A prostitute's client. 

  • That part of a variable resistor or potentiometer that rides over the resistance wire 

  • The selling of an unsound horse for a sound price is regarded by a Yorkshire jockey 

verb
  • To cheat or trick. 

  • To jostle by riding against. 

  • To maneuver (something) by skill for one's advantage. 

  • To ride (a horse) in a race. 

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