| Current (2) |
| Board of Directors | 2026 |
| Chairman | 2018 |
| Former (14) |
| Chairman | 1971 – 1992 |
| Board of Directors | 1971 – 2008 |
| Board of Directors | 1999 – 2001 |
| Board of Directors | 1971 – 1996 |
| Board of Directors | 1971 – 1995 |
| Board of Directors | 1971 – 1988 |
| Board of Directors | 2009 – 2018 |
| Board of Directors | 1971 – 1990 |
| Chairman | 1971 – 2013 |
| Chairman | 2013 – 2018 |
| Board of Directors | 1971 – 1990 |
| Board of Directors | 1971 – 1994 |
| Chairman | 1992 – 1996 |
| Board of Directors | 2008 – 2017 |