abacus vs score string

abacus

noun
  • A device used for performing arithmetical calculations; (rare) a table on which loose counters are placed, or (more commonly) an instrument with beads sliding on rods, or counters in grooves, with one row of beads or counters representing units, the next tens, etc. 

  • The uppermost portion of the capital of a column immediately under the architrave, in some cases a flat oblong or square slab, in others more decorated. 

  • A board, tray, or table, divided into perforated compartments for holding bottles, cups, or the like; a kind of buffet, cupboard, or sideboard. 

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