Region
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Romania
7
Russia (Federation)
12
Rwanda
2
Saint Kitts and Nevis
4
Saint Lawrence Seaway
1
Saint Lucia
5
Saint Vincent and the Grenadines
2
Samoa
1
San Marino
2
Sao Tome and Principe
1
Saskatchewan
1
Saudi Arabia
7
Senegal
4
Serbia
1
Seychelles
2
Sierra Leone
3
Singapore
4
Sint Maarten
1
Slavonia (Croatia)
1
Slovakia
3
Slovenia
5
Souris River Watershed
1
South Africa
6
South Sudan
2
Spain
6
Sri Lanka
1
Sudan
2
Suriname
1
Sweden
5
Switzerland
6
Tajikistan
1
Tanzania
3
Thailand
3
Trinidad and Tobago
7
Tropics
1
Tunisia
3
Turkey
10
Tuvalu
1
Uganda
1
Ukraine
10
United Arab Emirates
3
United States
741
Uruguay
2
Uzbekistan
3
Vanuatu
2
Venezuela
1
Vietnam
7
Virginia
1