non-paper vs pro memoria

non-paper

noun
  • A discussion paper which is not to form part of formal business, especially in the UN. 

adj
  • Used of information that is stored electronically 

  • Not made of paper 

pro memoria

noun
  • A document circulated in a meeting or summit for discussion purposes. 

  • A memory-aid; a reminder or memorandum, especially a book or document serving this purpose. 

How often have the words non-paper and pro memoria occurred in a corpus of books? (source: Google Ngram Viewer )