| Country | Action | Action Date | Effective Date |
|---|---|---|---|
| AUSTRIA | Signature | 12/10/1953 | |
| BELGIUM | Signature | 12/10/1953 | |
| DENMARK | Approval | 17/10/1974 | |
| FINLAND | Approval | 24/04/1974 | |
| FRANCE | Approval | 17/04/1980 | |
| GERMANY FEDERAL REPUBLIC | Definitive Signature | 12/10/1953 | |
| ITALY | Definitive Signature | 12/10/1953 | |
| NETHERLANDS THE | Definitive Signature | 12/10/1953 | |
| NORWAY | Approval | 09/11/1973 | |
| SWEDEN | Approval | 12/05/1977 | |
| SWITZERLAND | Approval | 29/04/1971 | |
| UNITED KINGDOM | Approval | 16/10/1980 | |
| UNITED KINGDOM | Accession | 15/06/1981 |