The CPI defines "the degree to which corruption is perceived to exist among public officials and politicians". It's conducted by an internation organization called Transparency Internation.
In short, it's a score given to each country representing how much it's people are corrupted.
Download 2006's results in PDF or HTML, then scroll down to the country list.
Check it out, Finland is on the Top of the list (a good thing), United States 20, Israel 34 and our beloved Egypt is 70. Our index value is dropping (getting more corrupted)from 3.4 in 2001 to 3.3 in 2006 making us move further down the list 
(worse and worse). But I wonder why? 
So if you're dreaming of becoming an official or a politician (are we allowed to dream of that too?), try to take the nationality of any country high in the list. And if not, like me and the rest of us, then you have nothing to worry about.