Fritz vs Rob

Fritz

name
  • A male given name from German. 

  • A name used to represent the German people (particularly the German armed forces) as a group. 

noun
  • A German person, usually male. 

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 Fritz and Rob occurred in a corpus of books? (source: Google Ngram Viewer )