The U.S. continues to be perceived as more corrupt than other developed world economies such as Germany, Japan, U.K, Canada and Australia, anti-graft watchdog Transparency International said in a report on Tuesday. But major emerging economies including China and India failed to improve popular perception about corruption in their countries compared to last year.

The 2013 edition of Corruption Perceptions Index once again ranked Denmark and New Zealand as the countries perceived to have the cleanest public sectors, while crises-ridden nations like Afghanistan, North Korea and Somalia were found to be the most corrupt among 177 countries in the survey.

“The top performers clearly reveal how transparency supports accountability and can stop corruption,” Huguette Labelle, who chairs Transparency International, said in a statement. “Still, the better performers face issues like state capture, campaign finance and the oversight of big public contracts which remain major corruption risks.”

Two-thirds of the countries ranked on a scale from zero to 100 -- zero being highly corrupt -- scored less than 50, indicating rampant corruption around the world. No country achieved a perfect score of 100, with the cleanest nations scoring only 90, while 43 was pegged as the worldwide average.

The U.S., which has drawn criticism over issues such as political donations and government contracts, and leniency on money laundering, still managed to be among the top 20 cleanest nations, with a score of 73, same as last year. Northern neighbor, Canada, in comparison ranked ninth on the list along with Australia. To the south, Mexico was ranked number 106.

China showed minimal improvement compared to last year with a ranking of 80 and a score of 40, amid an ongoing crackdown on corruption, which has led to the ouster of several top Communist Party politicians in the country. Another Asian giant, India, ranked even lower, at 94, with a score of 36, also unchanged from last year.

Spain, which was hit by a string of corruption scandals that showed how a nexus between politicians and construction companies ultimately led to a dangerous real estate bubble, lost 10 places to rank 40, with a score of 59 on the index.

Greece fared the worst among EU nations in the index, although it gained four points to climb to 80 on the list, with a score of 40.

Myanmar, which was ranked 157 with a score of 21, recorded the largest gain, as recent developments indicated that the country is steadily emerging out of almost half a century of military rule, amid significant corporate interest to set up businesses in the country.