(CNN) -- War-plagued Somalia, with its crumbling government infrastructure, is the world's most corrupt country, according to a global survey by the international watchdog Transparency International.
The group's annual Corruption Perception Index measures perceived levels of public sector corruption.
As was the case last year, the 2009 survey found that countries that scored lowest all have something in common: they are fragile, unstable and scarred by war or long-standing conflicts.
The group scored 180 countries on a scale of 0 (perceived to be highly corrupt) to 10 (perceived to have low levels of corruption).
Somalia scored 1.1.
Next came Afghanistan at 1.3, Myanmar at 1.4, and Sudan and Iraq -- both at 1.5
On the other end of the scale, New Zealand ranked highest at 9.4, followed by Denmark (9.3), Singapore and Sweden (9.2) and Switzerland (9.0).
The United States came it at 19 (7.5) and the United Kingdom was at 17 (7.7).
"When essential institutions are weak or non-existent, corruption spirals out of control and the plundering of public resources feeds insecurity and impunity," the group said.
On the other hand, countries that fared well in the survey have oversight to stem corruption. These include a well-performing judiciary, an independent media, and vigorous law enforcement, it said.