| Former (20) |
| Unofficial title | 1989 – 1994 |
| Unofficial title | 2002 – 2006 |
| Deputy | 2015 – 2018 |
| Unofficial title | 2002 – 2006 |
| Unofficial title | 1989 – 1994 |
| Audit | 1989 – 1990 |
| Management | 1989 – 1994 |
| Unofficial title | 1989 – 1998 |
| Unofficial title | 2002 – 2006 |
| Audit | 2013 – 2013 |
| Audit | 2013 – 2015 |
| Chief Executive Officer | 2014 – 2016 |
| Unofficial title | 1998 – 2002 |
| Management | 2014 – 2017 |
| Chief Executive Officer | 2011 – 2014 |
| Deputy | 2015 – 2016 |
| Audit | 2016 – 2016 |
| Chief Executive Officer | 2016 – 2018 |
| Unofficial title | 1998 – 2001 |
| Management | 1989 – 1990 |