While China has become the world's second largest economy, doing business in China is now perceived to be more corrupt, according to Transparency International.

China dropped five spots to 80th place out of 176 countries surveyed in the 2012 Corruption Perceptions Index. "The world's leading economies should lead by example, making sure that their institutions are fully transparent and their leaders are held accountable. This is crucial since their institutions play a significant role in preventing corruption from flourishing globally," said Cobus de Swardt, managing director of the Berlin-based corruption watchdog.

Denmark, Finland, New Zealand, Sweden and Singapore topped the list as the cleanest countries to do business in the world, according to the survey released Wednesday. Somalia, North Korea, Afghanistan, Sudan and Myanmar ranked at the bottom.

The United States was ranked 19th in the world, below Japan and the UK and ahead of Chile and Uruguay.

China isn't the only emerging economic giant to perform poorly on the index. India was ranked 94th, a step up from last year's ranking. Russia was 133rd, 10 places higher than 2011.

In Europe, Greece -- whose ailing economy faces tough austerity measures to meet international standards to get bailout cash -- plummeted to 94th place on the list, down from the 80th spot last year.

Corruption Perceptions Index 2012 -- Top 25

1. Denmark

1. (tie) Finland

1. (tie) New Zealand

4. Sweden

5. Singapore

6. Switzerland

7. Australia

7. (tie) Norway

9. Canada

9. (tie) Netherlands

11. Iceland

12. Luxembourg

13. Germany

14. Hong Kong

15. Barbados

16. Belgium

17. Japan

17. (tie) United Kingdom