Lum vs Rob

Lum

name
  • A diminutive of the male given name Columbus 

  • A surname from Chinese. 

  • An English surname transferred from the place name. 

Rob

name
  • A diminutive of the male given name Robert. 

  • A surname transferred from the given name, derived from Robert. 

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