puukko vs razor blade

puukko

noun
  • A type of sharp, pointed knife of Nordic heritage, with a short blade and flat back; normally worn in a sheath on the waist, and used for woodcrafts and as hunting knife. 

razor blade

noun
  • A thin piece of steel with a sharp edge that can be fitted into a razor. 

  • A replaceable cartridge in which razor blades are set, fitted into a razor. 

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