Jacky vs jacko

Jacky

noun

  • An aborigine. 

name

  • A nickname used instead of the male given name Jack, Jacques (and its cognates) or John. 

  • A diminutive of the female given name Jacqueline. 

jacko

noun

  • laughing kookaburra 

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