"Right now, do you think that economic conditions in the country as a whole are getting better or getting worse?"
http://pollingreport.com/consumer2.htm
from 1/31/1997 to 9/14/2007. That includes four of the fabulous 1990s. Still, the (linear) average changes are -.13 for "Better" and .16 for "Worse," respectively. The units are percentage points per (approx.) month. ("Same" and "Unsure" are trendless, and I ignored them.)
The peak in optimism (trough in pessimism) measured this way occurred in January 2004 -- I guess when people realized the Iraq adventure wouldn't be a cakewalk after all. From that point on, the linear trend has slopes (monthly changes) of -.39 (Better) and .38 (Worse), respectively. Pretty dramatic.