United States
1980
1985
1990
1995
2000
2005
2010
10,000
20,000
30,000
40,000
50,000
60,000
70,000
Australia
Austria
Belgium
Canada
Denmark
Estonia
Finland
France
Germany
Greece
Ireland
Israel
Italy
Luxembourg
Mexico
Netherlands
Norway
Poland
Spain
Sweden
Switzerland
United Kingdom
United States