The Corruption Perception Index scores 177 countries and territories on a scale from 0 (highly corrupt) to 100 (very clean).
No country has a perfect score, and two-thirds of countries score below 50. This indicates a serious, worldwide corruption problem.
Iran under mullahs score is 25 along with Central African Republic, Nigeria and Papua New Guinea.
The Corruption Perceptions Index 2013 serves as a reminder that the abuse of power, secret dealings and bribery continue to ravage societies around the world, the international group says.
Transparency International says: “The world urgently needs a renewed effort to crack down on money laundering, clean up political finance, pursue the return of stolen assets and build more transparent public institutions.”