Corruption lingers at the core of many of the world's underdeveloped nations.

Nigeria, the most populated country in Africa, is perceived to be the most corrupt among 60 countries evaluated, according to data from the 2016 Best Countries rankings. The rankings are a characterization of 60 countries based on a survey of more than 16,000 people from four regions.

In the survey, respondents answered how closely they related each of the 60 countries to the term "corrupt." Respondents were given no further specifications of the term, so interpretation of the word "corrupt" was left to survey respondents.

Elections in Nigeria face scrutiny, even though government accountability is seen as having improved. In 2015, President Maj. Gen. Muhammadu Buhari became the first opposition party candidate to win an election. As part of his presidential campaign, Buhari promised to crack down on corruption.

"When you fight corruption, it fights back," Nuhu Ribadu, the former chairman of Nigeria's Economic and Financial Crimes Commission, said in a TedX talk in Berlin.

[READ: Explore the rankings, data, video and news from Best Countries.]

Nigeria's former national security adviser, Sambo Dasuki, is scheduled to face trial on charges of fraud and money laundering, according to Bloomberg. It is the country's first high-profile corruption trial since Buhari took office.

In November, Nigerian President Muhammadu Buhari attributed this incident – and other alleged abuses of power – to the country's inability to defend itself from other threats, including Boko Haram, an extremist group that began its conquest in 2009 to create an Islamic state.

Russia, seen as the second-most powerful country in the world, is also seen as the sixth most corrupt.

Meanwhile, on the other side of the world, Colombia – a country synonymous with illegal drug kingpins like Pablo Escobar – gives Nigeria a run for its money as the second most corrupt country, based on perception.

Below are the 10 countries perceived to be the most corrupt, according to data from the 2016 Best Countries rankings.

Country Name Corrupt Rank
Nigeria 1
Colombia 2
Iran 3
Pakistan 4
Mexico 5
Russia 6
Algeria 7
Egypt 8
Kazakhstan 9
Bolivia 10