Year | Theme | Venue | # of participants |
1950 | I World Congress | Zurich, Switzerland | 81 |
1952 | II World Congress | Hague, Netherlands | 220 |
1955 | III World Congress | Stockholm, Sweden | 275 |
1958 | IV World Congress | Rome, Italy | 320 |
1961 | V World Congress | Paris, France | 425 |
1964 | VI World Congress | Geneva, Switzerland | 494 |
1967 | VII World Congress | Brussels, Belgium | 745 |
1970 | VIII World Congress | Munich, Germany | 894 |
1973 | IX World Congress | Montréal, Canada | 1,044 |
1976 | X World Congress | Edinburgh, Scotland | 1,081 |
1979 | XI World Congress | Moscow, Russia | 1,466 |
1982 | XII World Congress | Rio de Janeiro, Brazil | 1,477 |
1985 | XIII World Congress | Paris, France | 1,763 |
1988 | XIV World Congress | Washington DC, USA | 1,265 |
1991 | XV World Congress | Buenos Aires, Argentina | 1,400 |
1994 | XVI World Congress | Berlin, Germany | 1,884 |
1997 | XVII World Congress | Seoul, South Korea | 1,470 |
2000 | XVIII World Congress | Quebec, Canada | 1,849 |
2003 | XIX World Congress | Durban, South Africa | 1,011 |
2006 | XX World Congress | Fukuoka, Japan | 1,925 |
2009 | XXI World Congress | Santiago, Chile | 2,389 |
2012 | XXII World Congress | Madrid, Spain | 3,081 |
2014 | XXIII World Congress | Montréal, Canada | 2,323 |
2016 | XXIV World Congress | Poznań, Poland | 2,586 |
2018 | XXV World Congress | Brisbane, Australia | - |