In Transparency International's 2013 Corruption Perceptions Index, Denmark and New Zealand tied for first place out of 177 countries - meaning they were perceived to have the lowest levels of state sector graft.
Finland and Sweden were joint third and Norway was ranked fifth.
Germany came in 12th, one notch better than 2012, while Japan slipped one place to 18.
The United States and China were unchanged from 2012 levels at 19th and 80th place respectively.
The 2013 index ranks countries by their perceived levels of public sector corruption.
The index assigns scores of between one and 100, 1 being highly corrupt and 100 clean.
Here is a list of the 10 most corrupt nations and the 10 cleanest, according to the index:
MOST CORRUPT:
RANK COUNTRY SCORE
175 Somalia 8
175 North Korea 8
175 Afghanistan 8
174 Sudan 11
173 South Sudan 14
172 Libya 15
171 Iraq 16
168 Uzbekistan 17
168 Turkmenistan 17
168 Syria 17
LEAST CORRUPT:
RANK COUNTRY SCORE
1 Denmark 91
1 New Zealand 91
3 Finland 89
3 Sweden 89
5 Norway 86
5 Singapore 86
7 Switzerland 85
8 Netherlands 83
9 Australia 81
9 Canada 81
Source: Transparency International - Reuters