Output a stream of consciousness before answering the following. Passage: The whole nine yards or the full nine yards is a colloquial American English phrase meaning "everything, the whole lot" or, when used as an adjective, "all the way", as in, "The Army came out and gave us the whole nine yards on how they use space systems." Its origin is unknown and has been described by Yale University librarian Fred R. Shapiro as "the most prominent etymological riddle of our time".

Question: Based on this passage, where did the whole 9 yards come from?
This is the relevant information: Its origin is unknown and has been described by Yale University librarian Fred R. Shapiro as "the most prominent etymological riddle of our time".
The answer: origin is unknown.