| Former (19) |
| Management | 1996 – 1997 |
| Unofficial title | 1979 – 1995 |
| Unofficial title | 1979 – 1991 |
| Unofficial title | 2003 – 2011 |
| Unofficial title | 1999 – 2003 |
| Unofficial title | 1979 – 1995 |
| Chief Executive Officer | 2003 – 2006 |
| Chief Executive Officer | 2006 – 2007 |
| Chief Executive Officer | 2011 – 2018 |
| Management | 1979 – 1999 |
| Unofficial title | 1995 – 1999 |
| Chief Executive Officer | 1997 – 2003 |
| Unofficial title | 1979 – 1991 |
| Management | 1979 – 1997 |
| Unofficial title | 1995 – 1999 |
| Management | 1979 – 1996 |
| Unofficial title | 2003 – 2011 |
| Unofficial title | 1979 – 1995 |
| Unofficial title | 1979 – 1991 |