Crow vs ziggaboo

Crow

noun

  • A member of a Native American tribe of southern Montana. 

name

  • The Siouan language of this tribe. 

  • A surname. 

ziggaboo

noun

  • A nigger, negro; synonym of jigaboo. 

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