full score vs lead sheet

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. 

lead sheet

noun
  • A form of written music that specifies the melody, lyrics, and harmony. 

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