| Current (1) |
| Chief Executive Officer | 2023 |
| Former (17) |
| Management | 1971 – 1993 |
| Chief Executive Officer | 2016 – 2023 |
| Audit | 1971 – 2002 |
| Management | 1998 – 2002 |
| Management | 1971 – 1991 |
| Management | 2007 – 2009 |
| Management | 1971 – 1998 |
| Chief Executive Officer | 2013 – 2015 |
| Chief Executive Officer | 2016 – 2016 |
| Management | 2002 – 2006 |
| Management | 1971 – 1994 |
| Chief Executive Officer | 2009 – 2013 |
| Management | 1971 – 1996 |
| Management | 2006 – 2007 |
| Chief Executive Officer | 2015 – 2016 |
| Chief Executive Officer | 2013 – 2013 |
| Chief Executive Officer | 1971 – 1990 |