| Current (2) |
| Board of Directors | 2022 |
| Chairman | 2022 |
| Former (18) |
| Board of Directors | 2000 – 2004 |
| Chairman | 1985 – 2016 |
| Board of Directors | 2012 – 2014 |
| Board of Directors | 2008 – 2012 |
| Board of Directors | 2004 – 2006 |
| Board of Directors | 1975 – 1994 |
| Board of Directors | 1975 – 1995 |
| Board of Directors | 2014 – 2017 |
| Board of Directors | 1998 – 2000 |
| Chairman | 2016 – 2017 |
| Board of Directors | 2016 – 2017 |
| Board of Directors | 2017 – 2022 |
| Board of Directors | 2000 – 2001 |
| Chairman | 2017 – 2020 |
| Board of Directors | 1975 – 1998 |
| Board of Directors | 1975 – 1990 |
| Chairman | 2020 – 2022 |
| Board of Directors | 2006 – 2008 |