bowser vs servo

bowser

noun
  • A fuel metering/delivery pump at a filling station. 

  • A buffoon or imbecile. 

  • A road vehicle (often a trailer) for the transport of liquid fuel, particularly aviation fuel at an airfield. 

  • A mobile water tank deployed to distribute fresh water in emergency situations where the normal system of piped distribution has broken down or is insufficient. 

servo

noun
  • A service station, being a place to buy petrol for cars etc., as well as various convenience items, with or without actual car service facilities. 

  • A servomechanism or servomotor. 

verb
  • To control by means of servocontrol 

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