day job vs placement

day job

noun
  • One's principal job; one's regular means of income. 

placement

noun
  • The act of matching a person with a job 

  • A temporary posting of a person to a particular workplace to enable them to gain work experience. 

  • The zodiacal region of the sky in which the sun, moon, or a planet appears at the time and place of a person's birth. 

  • The act of placing or putting in place; the act of locating or positioning; the state of being placed. 

  • A location or position. 

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