Most countries have made "little to no progress” in tackling corruption in nearly a decade, a new report by Transparency International says.

The Berlin-based nonprofit group ranks countries on a scale of zero to 100, with 100 being the least corrupt.

According to its report, more than two-thirds of the 180 countries had a score below 50.

"The data shows that despite some progress, most countries still fail to tackle corruption effectively,” the group said in a statement.

The least corrupt countries are Denmark and New Zealand, with both scoring 88. They were followed by Finland, Singapore, Sweden and Switzerland, with scores of 85.

The most corrupt countries were South Sudan and Somalia, with scores of 12 each, followed by Syria with a score of 14, and Yemen and Venezuela with scores of 15.