clef vs full score

clef

noun
  • A symbol found on a musical staff that indicates the pitches represented by the lines and the spaces on the staff 

full score

noun
  • a large book showing all the notes of a composition with many simultaneous parts (instruments or voices), with all the parts shown in lines underneath each other in a fixed order. Commonly used by conductors. 

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