The lower-ranked countries in our index are plagued by untrustworthy and badly functioning public institutions like the police and judiciary.
Even where anti-corruption laws are on the books, in practice they're often skirted or ignored.
The global average score is a paltry 43, indicating endemic corruption in a country's public sector.
Top-scoring countries (yellow in the map below) are far outnumbered by orange and red countries where citizens face the tangible impact of corruption on a daily basis.
People frequently face situations of bribery and extortion, rely on basic services that have been undermined by the misappropriation of funds, and confront official indifference when seeking redress from authorities that are on the take. Cases like Petrobras and Odebrecht in Brazil or the saga of ex-President Viktor Yanukovych in Ukraine show how collusion between businesses and politicians siphons off billions of dollars in revenue from national economies, benefitting the few at the expense of the many.
In December 2015, governments from around the world came together to sign the Paris Agreement, agreeing to tackle climate change and keep global warming under two degrees centigrade.
Read more Middle East and North Africa: Despite the political changes that shook the Arab region six years ago, the hope for Arab countries to fight corruption and end impunity has not seen any progress yet.
This explains the sharp drop of most of Arab countries on the 2016 index – 90 percent of these have scored below 50, which is a failing grade.
Learn more about public sector corruption in your region below.
Americas: From the Panama Papers in April to the record US.5 billion Odebrecht settlement in Brazil in December, 2016 was a good year in the fight against corruption in the Americas. Read more Asia Pacific: Unfortunately, the majority of Asia Pacific countries sit in the bottom half of this year’s Corruption Perceptions Index.