razor wire vs score string

razor wire

noun
  • A form of securing wire similar to barbed wire, but with a series of short blades instead of barbs. Also, a length thereof. 

score string

noun
  • A wire strung with beads and hung horizontally above or near the table which is used to keep score. 

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