Okay, this is first-rate second-hand input. One of the program directors I interviewed with stated that the "average" program usually doesn't dip on the rank list below 3x the number of seats in the program (e.g. if the program has 3 seats, they usually don't go below #9 on the list). The other thing he said is that it is rare for a program to match someone below the top 3rd of the program's rank list. This is one PD's statement mind you.
I don't know if these 2 scenarios always jive, and I don't know what he meant by "average" program. Some inside scoop from a resident privy to such info would certainly be helpful with this question.