The Corruption Perceptions Index

According to this index New Zealand is the world's least corrupt country. Somalia is most corrupt. Canada sits at number 8.

The Corruption Perceptions Index (CPI) table shows a country's ranking and score, the number of surveys used to determine the score, and the confidence range of the scoring.
The rank shows how one country compares to others included in the index. The CPI score indicates the perceived level of public-sector corruption in a country/territory.

See the CPI 2009 Table