| Former (15) |
| Management | 1992 – 1993 |
| Unofficial title | 2007 – 2011 |
| Unofficial title | 2007 – 2009 |
| Management | 2003 – 2007 |
| Management | 1992 – 2002 |
| Unofficial title | 1998 – 2002 |
| Unofficial title | 1992 – 1998 |
| Chief Executive Officer | 2013 – 2014 |
| Chief Executive Officer | 2008 – 2011 |
| Chief Executive Officer | 2011 – 2013 |
| Chief Executive Officer | 2006 – 2008 |
| Unofficial title | 1998 – 2002 |
| Unofficial title | 2002 – 2007 |
| Unofficial title | 2011 – 2012 |
| Management | 2002 – 2003 |