bumf vs printed matter

bumf

noun
  • Useless papers; now especially official documents, standardized forms, sales and marketing print material, etc. 

printed matter

noun
  • Printed material produced by printers and publishers, including books, magazines, brochures, booklets, publicity material and newspapers, especially in relation to cheaper postage rates on such material. 

How often have the words bumf and printed matter occurred in a corpus of books? (source: Google Ngram Viewer )