| Former (15) |
| Management | 1997 – 2001 |
| Unofficial title | 1995 – 2002 |
| Unofficial title | 2007 – 2008 |
| Unofficial title | 1999 – 2000 |
| Unofficial title | 2007 – 2009 |
| Management | 2007 – 2009 |
| Unofficial title | 2003 – 2005 |
| Management | 1977 – 1997 |
| Chief Executive Officer | 1977 – 2007 |
| Unofficial title | 2005 – 2007 |
| Unofficial title | 1977 – 1994 |
| Unofficial title | 1999 – 2003 |
| Chief Executive Officer | 1977 – 1992 |
| Management | 2001 – 2003 |
| Management | 1977 – 1994 |