Transparency International

Transparency International(TI) defines corruption as the abuse of entrusted power for private gain. This definition encompasses corrupt practices in both the public and private sectors. The Corruption Perceptions Index (CPI) ranks countries according to the perception of corruption in the public sector. The CPI is an aggregate indicator that combines different sources of information about corruption, making it possible to compare countries. The CPI ranks almost 200 countries by their perceived levels of corruption, as determined by expert assessments and opinion surveys.

Global Corruption Barometer is the largest world-wide public opinion survey on corruption - See more at: http://www.transparency.org/gcb2013/in_detail#sthash.hey9okGH.dpuf