doorman vs security guard

doorman

noun
  • A person who holds open the door at the entryway (entrance) to a building, summons taxicabs, and provides an element of security; in apartment buildings, he also accepts deliveries and may perform certain concierge type services. 

security guard

noun
  • A person who is employed to provide security for people or property. 

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