When walking up/down stairs, what percentage of the sole of your foot comes in to contact with the step you are on?
I've just walked down some stairs, y'see. If you'd asked me beforehand I would have guessed at around 95%, but it must have actually been anywhere between 50% and 70%.
I do have quite big feet, though.
(thinly veiled I've-just-walked-down-some-stairs thread)