| Former (14) |
| Management | 1944 – 2003 |
| Unofficial title | 1944 – 1993 |
| Unofficial title | 2005 – 2006 |
| Management | 1944 – 1988 |
| Deputy | 2000 – 2004 |
| Chief Executive Officer | 2004 – 2006 |
| Audit | 1944 – 1988 |
| Chief Executive Officer | 2006 – 2009 |
| Unofficial title | 2001 – 2005 |
| Chief Executive Officer | 2004 – 2004 |
| Management | 1944 – 1988 |
| Unofficial title | 1944 – 1990 |
| Unofficial title | 1944 – 2001 |
| Unofficial title | 1944 – 1993 |