Colt vs derringer

Colt

noun
  • A revolver (gun) (from Colt's Manufacturing Company), associated especially but not exclusively with the American Wild West. 

name
  • A male given name transferred from the surname. 

  • A surname originating as an occupation. 

derringer

noun
  • A type of very small, concealable pistol with one or two barrels, but without any loading system or magazine. 

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