cootie vs cooty

cootie

noun
  • Any germ or contaminant, real or imagined, especially from the opposite gender (for pre-pubescent children). 

  • A sideswiper, a type of telegraph key. 

  • A louse (Pediculus humanus). 

  • A nest-building female American coot (counterpart to cooter). 

cooty

adj
  • Afflicted with body lice or coots. 

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