Just for fun, I looked at the 1929-1941 (13 year) period using Alec's toy.
BTW, these are annualized returns while the OP was talking about total damage during the period.
S&P 500: -1.7%
And then the best period in history (1982-1999):
S&P 500: 14.7%
Quite a range, eh?
Favorite ERF quote: "I'm not going to waste my time on someone who's more interested in being stubborn or obtuse or intolerant." -- Nords
Favorite ERF error message: "Sorry Nords is a moderator/admin and you are not allowed to ignore him or her."