Nearly three quarters of states, beginning with those at war such as Iraq or Afghanistan, are seen as seriously corrupt, according to Transparency International.
Financial scandals and the influence of money in politics are helping make the United States more corrupt, says the Berlin-based corruption watchdog.
In its latest index, it warns governments about the effects of corruption on efforts to bail out markets and fight poverty and climate change.
The world’s least corrupt nations are the same as last year: Denmark, New Zealand and Singapore.
Britain is classed as the 20th least corrupt.
The most corrupt are Afghanistan, Myanmar – and, bottom of the heap, Somalia.
For the first time, the US is not among the top 20 least corrupt nations.
“It seems to be a trend that in the US, not only the main impact of the financial crisis, which affected other countries as well, but also the many, many, municipal corruption scandals… have really influenced the way people think about the public sector and integrity,” said Robin Hodess, Transparency International’s policy director. “And don’t forget as well that there is some concern about the role of money in politics in the US.”
Russia’s anti-corruption drive has made little difference: it sits alongside countries like Kenya and Congo, classed among the world’s 25 most corrupt nations.
The watchdog says several countries have improved their performance since last year, but that much more effort was needed.
The index was compiled based on surveys with business people and other experts.