fad vs vocation

fad

noun
  • A phenomenon that becomes popular for a very short time. 

vocation

noun
  • An inclination to undertake a certain kind of work, especially a religious career; often in response to a perceived summons; a calling. 

  • An occupation for which a person is suited, trained or qualified. 

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