| Current (3) |
| Chairman | 2017 |
| Board of Directors | 2017 |
| Board of Directors | 2023 |
| Former (15) |
| Board of Directors | 1972 – 1998 |
| Board of Directors | 1997 – 1999 |
| Chairman | 2008 – 2017 |
| Board of Directors | 1972 – 1992 |
| Board of Directors | 1972 – 1988 |
| Board of Directors | 2001 – 2009 |
| Board of Directors | 1972 – 1995 |
| Board of Directors | 1972 – 1988 |
| Board of Directors | 1972 – 1989 |
| Board of Directors | 1995 – 1996 |
| Board of Directors | 1999 – 2001 |
| Board of Directors | 1996 – 1997 |
| Board of Directors | 1972 – 1991 |
| Board of Directors | 1972 – 1989 |
| Board of Directors | 1996 – 1997 |