90% off is doomer fantasy. It is hard to conceive how the Detroit scenario could happen to the whole nation. If it does, the places with jobs will retain much more value than places without.

I don’t have Detroit historical wage info but I found this site which shows by zipcode income and housing prices.

http://realestate.aol.com/Detroit-MI-neighborhood

Take a look on realtor.com just for fun to see what you can get for your money.

Also see this price heat map:

http://www.trulia.com/home_prices/Michigan/Detroit-heat_map/

I found a site that claimed the average (not median)city price peaked in 2003 at just under $98,000. Last August it was $11,600.

http://mjperry.blogspot.com/2009/08/average-home-price-in-detroit-falls-to.html

Here is the population data from wiki (from the census peak):

Census City Metro Region
1950 1,849,568 3,219,256 3,700,490
1960 1,670,144 4,012,607 4,660,480
1970 1,514,063 4,490,902 5,289,766
1980 1,203,368 4,387,783 5,203,269
1990 1,027,974 4,266,654 5,095,695
2000 951,270 4,441,551 5,357,538
2008* 912,062 4,425,110 5,354,225
*Estimate