Sing vs Sonde

Sing

name

  • a Sikh surname 

  • A surname from Chinese. 

  • A surname from English [in turn originating as an occupation]. 

Sonde

name

  • A dialect of Kikongo language 

  • A Bantu language 

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