cooker vs water boiler

cooker

noun
  • A device for heating food, a stove. 

  • A person who is cooked; a crazy person. 

  • A person who makes or uses illicit drugs, especially methamphetamine or cannabis. 

  • An appliance or utensil for cooking food. 

  • A cooking apple. 

water boiler

noun
  • An electric device which heats water up to boiling temperature. 

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