barbed wire vs score string

barbed wire

noun
  • Twisted strands of steel wire, often coated with zinc, having barbs evenly spaced along them; used to construct agricultural and military fences. 

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 barbed wire and score string occurred in a corpus of books? (source: Google Ngram Viewer )