| Former (22) |
| Chief Executive Officer | 2006 – 2006 |
| Management | 1990 – 1995 |
| Audit | 1990 – 1991 |
| Audit | 1999 – 2001 |
| Chief Executive Officer | 2001 – 2001 |
| Chief Executive Officer | 2013 – 2017 |
| Chief Executive Officer | 2009 – 2010 |
| Unofficial title | 2017 – 2018 |
| Management | 2001 – 2006 |
| Chief Executive Officer | 1997 – 2000 |
| Management | 2006 – 2009 |
| Chief Executive Officer | 2013 – 2013 |
| Management | 2000 – 2001 |
| Management | 2000 – 2001 |
| Management | 2000 – 2001 |
| Chief Executive Officer | 2010 – 2013 |
| Audit | 1990 – 1994 |
| Management | 1990 – 1991 |
| Management | 1996 – 1997 |
| Management | 2000 – 2001 |
| Management | 1997 – 1998 |
| Chief Executive Officer | 2000 – 2001 |