Generally, European nations tend not to experience high levels of corruption when compared with nations in other parts of the world.

While EU member states enjoy relatively low levels of corruption, there's still a surprisingly varied level of corruption from one European nation to another.

The anti-corruption nongovernmental organization Transparency International has compiled a Corruption Perceptions Index using 13 surveys and expert assessments to give countries "corruption scores."

According to Transparency International, a global anti-corruption nongovernmental organization, the European Union is one of the least corrupt areas in the world.

But while it may well be the case that Europe experiences low levels of corruption relative to the rest of the world, there's still room for improvement, as well as considerable disparity in corruption levels from one nation to the next.

The organization has put together another edition of its annual Corruption Perceptions Index, drawing on 13 surveys and expert assessments to measure public-sector corruption in 180 countries and territories. Each country is given a score from zero (highly corrupt) to 100 (very clean).

Countries with high levels of corruption can be dangerous spots for political opponents — practically all countries where political killings are ordered or condoned by the government are rated as highly corrupt on the CPI, according to the organization.

Below are the 13 most corrupt countries in the European Union, according to Transparency International's Corruption Perceptions Index.