mushhead vs pinhead

mushhead

noun
  • A stupid person. 

pinhead

noun
  • A foolish or stupid person. 

  • The head of a pin. (Frequently used in size comparisons.) 

  • A telemark skier. 

  • A newborn cricket used as food for pets. 

  • A human head that is unusually tapered or small, often due to microcephaly, or a person with that trait. Often promoted in freak shows as "human pinheads". 

  • The immature juvenile fruiting body of a mushroom prior to its gills opening. 

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