| Former (15) |
| Unofficial title | 1998 – 2006 |
| Chief Executive Officer | 2004 – 2004 |
| Management | 1998 – 2004 |
| Management | 2008 – 2009 |
| Management | 2008 – 2008 |
| Management | 2006 – 2007 |
| Management | 1979 – 1989 |
| Chief Executive Officer | 2004 – 2006 |
| Management | 2005 – 2006 |
| Chief Executive Officer | 2007 – 2008 |
| Unofficial title | 1998 – 2003 |
| Management | 1979 – 1997 |
| Unofficial title | 2003 – 2006 |
| Audit | 1979 – 1989 |
| Unofficial title | 2009 – 2009 |
