Region
United States
618
Montana
534
Colorado
436
Wyoming
395
New Mexico
385
Nevada
273
California
263
Oregon
258
Idaho
248
Arizona
201
Washington (State)
186
Utah
168
Pennsylvania
161
China
157
États-Unis
155
Great Britain
109
South Dakota
74
New Jersey
67
India
65
North Dakota
61
Africa
60
England
57
California Desert National Conservation Area (Calif.)
46
Mexico
44
Australia
37
Brazil
37
Developing countries
36
Italy
36
Alaska
35
Europe
35
Bolivia
33
West Virginia
33
Colombia
32
New York (State)
28
California Desert National Conservation Area
27
Scotland
27
West (U.S.)
27
Kenya
26
France
25
Spain
25
Argentina
23
South Africa
22
Peru
21
Canada
20
Grande-Bretagne
19
Texas
19
Zimbabwe
19
Afrique
17
Ireland
17
Arkansas
15
more ...