| Former (20) |
| Unofficial title | 2003 – 2005 |
| Unofficial title | 1977 – 1995 |
| Unofficial title | 2001 – 2003 |
| Deputy | 2001 – 2003 |
| Chief Executive Officer | 2001 – 2005 |
| Management | 1977 – 1991 |
| Unofficial title | 1977 – 1991 |
| Audit | 1977 – 2002 |
| Unofficial title | 2001 – 2005 |
| Chief Executive Officer | 1996 – 2000 |
| Unofficial title | 1977 – 1991 |
| Management | 2000 – 2002 |
| Unofficial title | 1995 – 1999 |
| Management | 1977 – 1988 |
| Management | 1977 – 1988 |
| Management | 1992 – 1993 |
| Management | 1977 – 1993 |
| Unofficial title | 1977 – 1995 |
| Unofficial title | 1999 – 2001 |
| Management | 1993 – 1996 |
