| Former (18) |
| Chief Executive Officer | 2001 – 2004 |
| Unofficial title | 2004 – 2008 |
| Management | 1989 – 1994 |
| Chief Executive Officer | 2004 – 2007 |
| Management | 1989 – 1991 |
| Management | 1989 – 1989 |
| Unofficial title | 2008 – 2012 |
| Unofficial title | 2008 – 2012 |
| Unofficial title | 1999 – 2000 |
| Chief Executive Officer | 2000 – 2001 |
| Management | 2011 – 2012 |
| Unofficial title | 1999 – 2000 |
| Unofficial title | 2003 – 2004 |
| Chief Executive Officer | 2011 – 2013 |
| Management | 1999 – 2000 |
| Management | 1989 – 1997 |
| Management | 1989 – 1992 |
| Management | 2011 – 2013 |