| Former (19) |
| Chief Executive Officer | 2002 – 2004 |
| Management | 1967 – 1995 |
| Management | 1967 – 2001 |
| Unofficial title | 1967 – 1989 |
| Chief Executive Officer | 2001 – 2002 |
| Chief Executive Officer | 1967 – 1992 |
| Unofficial title | 1999 – 2008 |
| Management | 1967 – 1989 |
| Unofficial title | 2008 – 2009 |
| Unofficial title | 1967 – 1991 |
| Unofficial title | 2008 – 2009 |
| Chief Executive Officer | 2004 – 2005 |
| Unofficial title | 1967 – 1999 |
| Unofficial title | 2004 – 2008 |
| Chief Executive Officer | 2005 – 2007 |
| Unofficial title | 1999 – 2004 |
| Unofficial title | 1967 – 1991 |
| Chief Executive Officer | 2007 – 2009 |
| Management | 2004 – 2004 |
