BERLIN (Reuters) - Brazil suffered the sharpest deterioration in public perceptions of corruption last year, global watchdog Transparency International (TI) said in its annual report published on Wednesday that showed graft remains pervasive worldwide.

The TI report measures perceptions of graft rather than actual levels due to the secrecy surrounding most corrupt dealings.

Denmark retained the top spot in the rankings as the country perceived as most clean, while North Korea and Somalia were the worst performers, each scoring just eight on the TI scale to 100.

The United States ranked as 16^th least corrupt, tying in that spot with Austria.

Brazil tumbled to 76th place out of 168 countries, down seven positions from 2014. Latin America's largest economy was rocked by a massive corruption scandal at state-run companies, including oil giant Petroleo Brasileiro SA (Petrobras), which involved allegations against top government officials.

Other decliners last year included Libya, Australia, Spain and Turkey. Turkey, which saw one of the sharpest declines in 2014 as a major corruption scandal buffeted the ruling Islamist-rooted AK Party, fell a further three points.

Two thirds of the 168 countries assessed scored below the 50 mark in TI's scale where 100 stands for the most clean and 0 for the most corrupt, indicating that corruption continues to take a heavy toll on the global economy and governance.

On a brighter note, however, the survey showed general perceptions of corruption around the world had declined in 2015.

Among countries which saw an improved ranking were Greece, Senegal and Britain.

TI attributed the overall global improvement to the work of citizen activists fighting corruption in places such as Guatemala, Sri Lanka and Ghana - all countries which were able to improve their ratings in 2015.

"Corruption can be beaten if we work together," said TI chairman Jose Ugaz in a statement. "To stamp out the abuse of power, bribery and shed light on secret deals, citizens must together tell their governments they have had enough."

Reporting by Tina Bellon.

To Learn More:

            Corruption Perceptions Index 2015: Report (Transparency International)

Corruption Perceptions Index 2015: Results (Transparency International)

This is the Only Country that Ranks Worse than North Korea on the World Press Freedom Index (by Steve Straehley and David Wallechinsky, AllGov)

Is This the Most Corrupt Town in the U.S.? (by Noel Brinkerhoff and Danny Biederman, AllGov)

Iceland Ranked World’s Most Peaceful Nation, Somalia Worst; U.S. Improves to 82^nd (by Noel Brinkerhoff, AllGov)