| Former (19) |
| Deputy | 1969 – 1995 |
| Chief Executive Officer | 2008 – 2009 |
| Deputy | 1969 – 1995 |
| Deputy | 1969 – 1999 |
| Deputy | 1969 – 1991 |
| Management | 1969 – 1988 |
| Chief Executive Officer | 2010 – 2022 |
| Management | 2022 – 2022 |
| Deputy | 1996 – 1999 |
| Deputy | 1999 – 2007 |
| Audit | 1969 – 1988 |
| Deputy | 1969 – 1991 |
| Unofficial title | 2022 – 2022 |
| Chief Executive Officer | 2003 – 2008 |
| Deputy | 1999 – 2003 |
| Chief Executive Officer | 2009 – 2010 |
| Chief Executive Officer | 2002 – 2003 |
| Management | 1969 – 2002 |
| Chief Executive Officer | 1969 – 1987 |