Table listing the 48 Participating Governments and their respective year of adherence.
| Argentina (1994) | Cyprus (2000) | Ireland (1984) | New Zealand (1994) | South Africa (1995) |
| Australia (1978) | Czech Republic (1978*) | Italy (1978) | Norway (1989) | Spain (1988) |
| Austria (1991) | Denmark (1984) | Japan (1974) | Poland (1978) | Sweden (1978) |
| Belarus (2000) | Estonia (2004) | Kazakhstan (2002) | Portugal (1986) | Switzerland (1978) |
| Belgium (1978) | Finland (1980) | Latvia (1997) | Romania (1990) | Türkiye (2000) |
| Brazil (1996) | France (1974) | Lithuania (2004) | Rep. of Korea (1995) | Ukraine (1996) |
| Bulgaria (1984) | Germany (1974) | Luxembourg (1984) | Russia (1974) | U.K. (1974) |
| Canada (1974) | Greece (1984) | Malta (2004) | Serbia (2013) | U.S. (1974) |
| China (2004) | Hungary (1985) | Mexico (2012) | Slovakia (1978*) | |
| Croatia (2005) | Iceland (2009) | Netherlands (1978) | Slovenia (2000) |
(* Czechoslovakia separated into the Czech Republic and Slovakia – participation date 5 Mar 1993)