commentary vs marginal note

commentary

noun
  • A brief account of transactions or events written hastily, as if for a memorandum. 

  • A series of comments or annotations; especially, a book of explanations or expositions on the whole or a part of some other work. 

  • An oral relation of an event, especially broadcast by television or radio, as it occurs. 

marginal note

noun
  • A note in the margin of a document. 

How often have the words commentary and marginal note occurred in a corpus of books? (source: Google Ngram Viewer )