ledger vs magnum opus

ledger

noun
  • A book for keeping notes; a record book, a register. 

  • A large, flat stone, especially one laid over a tomb. 

  • A distributed ledger, a public financial transaction database, typically using a blockchain. 

  • A board attached to a wall to provide support for attaching other structural elements (such as deck joists or roof rafters) to a building. 

  • A book or other scheme for keeping accounting records. 

  • A collection of accounting entries consisting of credits and debits. 

verb
  • To use (a certain type of bait) in bottom fishing. 

  • To engage in bottom fishing. 

  • To record (something) in, or as if in, a ledger. 

magnum opus

noun
  • A great or important work of literature, music or art, a masterpiece. 

  • The best, most popular, or most renowned achievement of an author or artist, representing their major life effort. 

  • The process of working with the prima materia to create the philosopher's stone. 

How often have the words ledger and magnum opus occurred in a corpus of books? (source: Google Ngram Viewer )