Zimbabwe Protest
Protesters calling for Zimbabwean President Robert Mugabe to step down cheer in front of a military vehicle in Harare, Zimbabwe, in November 2017.
REUTERS/Philimon Bulawayo
The World Economic Forum on Tuesday released its annual corruption index as part of its " Global Competitiveness Report."

Using a methodology linked to Transparency International's Corruption Perception Index, the WEF ranked 140 countries' level of corruption within their society on a scale of one to 100.

A score of 100 means a country is without corruption, while zero is the most corrupt possible. All the countries featured on this list scored 30 or less.

The countries the WEF views as most corrupt tend to be in Africa, Central America, and the Middle East, in societies with weak legal and governmental systems and widespread poverty.

For instance, the WEF ranked Yemen, which is in the middle of a brutal civil war, as the most corrupt nation. But a handful of the world's 20 largest economies also made it onto the list.

Check out the world's most corrupt nations below.

T29. Sierra Leone — 30

Riot police in the streets of Sierra Leone's capital, Freetown, in September 2007.
REUTERS/Katrina Manson

T29. Iran — 30

Iran's special forces marching during the annual Army Day parade near the Khomeini shrine in southern Tehran.
Morteza Nikoubazl/Reuters

T29. Ukraine — 30

A Ukrainian serviceman at a checkpoint near the town of Horlivka, in eastern Ukraine, in September 2014.
REUTERS/David Mdzinarishvili

T29. Gambia — 30

Gambia's Army forces in a stadium in Banjul, Gambia.
Thomson Reuters

T22. Russia — 29

Matthew Stockman / Getty

T22. Paraguay — 29

Reuters/Stringer

T22. Mexico — 29

Diego Grandi/Shutterstock

T22. Laos — 29

Laos girls in ancient dress parade during the Songkran festival in April 2008 in Luang Prabang, Laos.
Chumsak Kanoknan/Getty Images

T22. Kyrgyzstan — 29

Reuters

T22. Dominican Republic — 29

The Dominican Republic celebrates at the World Baseball Classic in 2013.
Thearon W. Henderson/Getty Images

T22. Honduras — 29

People at a march in Tegucigalpa in July 2015 to demand the resignation of Honduran President Juan Orlando Hernandez.
REUTERS/Jorge Cabrera

T19. Guatemala — 28

Reuters/Stringer

T19. Bangladesh — 28

Andrew Biraj/Reuters

T19. Mauritania — 28

REUTERS/Joe Penny

T17. Lebanon — 28

Jerry Lampen/ Reuters

T17. Kenya — 28

Kenyan police clashing with a protester.
Goran Tomasevic/Reuters

T15. Guinea — 27

Children scavenge at a public dump in Malabo in January 2012.
Reuters

T15. Nigeria — 27

Getty Images

T13. Uganda — 26

Flickr/Tore

T13. Nicaragua — 26

Reuters/Oswaldo Rivas

T11. Cameroon — 25

A member of a civilian vigilante group and a woman pumping water into jerrycans in Kerawa, which is on the border with Nigeria and subject to frequent attacks by the militant group Boko Haram.
REUTERS/Joe Penney

T11. Mozambique — 25

Thomson Reuters

T8. Haiti — 22

Demonstrators hold signs and Haitian flags as a motorcade with US President Donald Trump motorcade passes in West Palm Beach, Florida, in January.
Thomson Reuters

T8. Burundi — 22

Burundi's president, Pierre Nkurunziza.
Evrard Ngendakumana/Reuters

T8. Zimbabwe — 22

Protesters calling for Zimbabwean President Robert Mugabe to step down cheer in front of a military vehicle in Harare, Zimbabwe, in November 2017.
REUTERS/Philimon Bulawayo

T5. Democratic Republic of Congo — 21

Soldiers from the Armed Forces of the Democratic Republic of Congo near the town of Kimbau in February.
Reuters

T5. Cambodia — 21

A man holding a Cambodian flag outside the US Embassy in Phnom Penh.
REUTERS/Samrang Pring

T5. Tajikistan — 21

Brendan Smialowski/Pool/Reuters

4. Chad — 20

A Chadian soldier on a pickup truck next to a bag of rocket-propelled grenades in Gambaru in 2015.
Emmanuel Braun/Reuters

3. Angola — 19

Reuters/Claudia Daut

2. Venezuela — 18

A Venezuelan protester in front of a burning barricade during riots in Caracas in March 2004.
REUTERS/Jorge Silva

1. Yemen — 16

An armed Houthi follower at a rally against Saudi-led airstrikes in Sanaa in June 2015.
Reuters