missive vs sheet music

missive

noun
  • A written message; a letter, note or memo. 

  • Letters sent between two parties in which one makes an offer and the other accepts it. 

adj
  • Specially sent; intended or prepared to be sent. 

sheet music

noun
  • Handwritten or printed form of musical notation. 

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