Bozo vs Yay

Bozo

name
  • The Mande language of these people. 

noun
  • A member of a West African ethnic group located predominantly along the Niger River in Mali, famous for their fishing. 

Yay

name
  • A branch of the Tai language family, spoken by the Bouyei and Giáy people. 

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