A new way to look at plunging home prices

This San Francisco Chronicle report on the most recent update to the Case-Shiller Home Price Indices presents an interesting new way to look at home price declines in the 20 cities the index tracks. The bigger the blue bubble below, the bigger the housing bubble in 2005.
Well, actually, that's not completely true, areas like Detroit and, to a lesser extent, Cleveland and Dallas, are getting a housing bust without ever having had much of a bubble...