Transparency International regularly publishes the Corruption Perceptions Index (CPI), which, roughly speaking, measures how corrupt the public sector of each country is (corruption in private companies does not influence the results).
The name of the index may make it seem rather imprecise (it is based on “perceptions”, after all, not on the actual amount of corruption), but the problem with corruption is that most of it has never been publicly uncovered. That’s why Transparency International collects studies from various institutions analysing corruption in the world by surveying businessmen and local experts.
Here are the results for South and Central America (100 would be a country practically devoid of corruption, while 0 means a huge amount of corruption at all levels of society):
For comparison, here are some other major economies:
If you are interested in the scores of other European countries, see my article on the Corruption Perceptions Index of European countries.