noggin vs wetback

noggin

noun
  • The head. 

  • A signalling molecule involved in embryo development, producing large heads at high concentrations. 

  • A small measure of spirits equivalent to a gill. 

  • A small mug, cup or ladle; the contents of such a container. 

wetback

noun
  • A person of the mestizo race; a mojado. 

  • A Mexican or Central American who illegally enters the United States of America from its southern border. 

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