Región
Developing countries
4
Europe
4
United States
4
European Union countries
3
Great Britain
3
Japan
2
Africa
1
Africa, Sub-Saharan
1
Asia
1
Canada
1
England
1
India
1
Indonesia
1
Niger River Delta
1
Nigeria
1
North America
1
Northwest, Pacific
1
Russia (Federation)
1
South Asia
1
Sweden
1
Taiwan
1
Turkey
1