This chart shows the variance between different polls -- which is why comparing one poll, such as CNN, with another, such as FOX, is problematic. What's needed is a trend, like this one, across a longer period of time.
Bush Aggregated Approval Ratings, Second Term
From Kathy Gill, About.com Guide
This image is from Steve Ruggles, University of Minnesota
Bush Approval Ratings, Aggregated - Second Term - 29 June 2008
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