fire engine vs firefighter

fire engine

noun
  • A vehicle used by firefighters to pump water to fight a fire. Typically, a fire engine carries a supply of water and has the ability to connect to an external water supply. 

firefighter

noun
  • A person who has been trained to put out fires. 

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