| Former (16) |
| Management | 2007 – 2007 |
| Unofficial title | 1984 – 1998 |
| Unofficial title | 1984 – 2002 |
| Management | 1984 – 1995 |
| Unofficial title | 2006 – 2008 |
| Chief Executive Officer | 2008 – 2011 |
| Unofficial title | 2002 – 2006 |
| Management | 2008 – 2010 |
| Unofficial title | 1984 – 1993 |
| Management | 2007 – 2008 |
| Chief Executive Officer | 2004 – 2007 |
| Unofficial title | 2008 – 2011 |
| Unofficial title | 2002 – 2006 |
| Unofficial title | 1984 – 1990 |
| Unofficial title | 1984 – 1988 |
| Management | 2004 – 2004 |