This Transparency International report measures domestic and public sector corruption; the organization states, "The Corruption Perceptions Index (CPI) ranks countries according to perception of corruption in the public sector. The CPI is an aggregate indicator that combines different sources of information about corruption, making it possible to compare countries."
The 2010 CPI finds that "nearly three quarters of the 178 countries in the index score below five, on a scale from 0 (perceived to be highly corrupt) to 10 (perceived to have low levels of corruption), indicating a serious corruption problem.
...Denmark, New Zealand and Singapore tie for first place with scores of 9.3. Unstable governments, often with a legacy of conflict, continue to dominate the bottom rungs of the CPI. Afghanistan and Myanmar share second to last place with a score of 1.4, with Somalia coming in last with a score of 1.1."