custodian vs portress

custodian

noun
  • A person entrusted with the custody or care of something or someone; a caretaker or keeper. 

  • a janitor; a cleaner 

portress

noun
  • a female porter (person in control of the entrance to a building) 

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