| Former (17) |
| Management | 2012 – 2014 |
| Chief Executive Officer | 2009 – 2010 |
| Management | 1981 – 2007 |
| Management | 1998 – 2001 |
| Management | 2001 – 2007 |
| Management | 2008 – 2009 |
| Management | 1999 – 1999 |
| Management | 2011 – 2012 |
| Chief Executive Officer | 2007 – 2008 |
| Management | 1981 – 1998 |
| Audit | 1981 – 1989 |
| Management | 2012 – 2012 |
| Management | 2014 – 2015 |
| Unofficial title | 2015 – 2016 |
| Management | 2015 – 2015 |
| Chief Executive Officer | 2010 – 2011 |
| Deputy | 1981 – 1987 |