| Former (15) |
| Audit | 1991 – 2000 |
| Chief Executive Officer | 2013 – 2016 |
| Chief Executive Officer | 2006 – 2011 |
| Unofficial title | 2001 – 2007 |
| Chief Executive Officer | 1991 – 2001 |
| Chief Executive Officer | 2016 – 2019 |
| Unofficial title | 1997 – 2001 |
| Management | 2001 – 2001 |
| Management | 2001 – 2001 |
| Unofficial title | 2003 – 2007 |
| Founder | 1991 – 2019 |
| Unofficial title | 1997 – 2001 |
| Unofficial title | 2001 – 2003 |
| Management | 2001 – 2006 |
| Founder | 1991 – 2019 |