| Current (2) |
| Chairman | 2022 |
| Board of Directors | 2022 |
| Former (14) |
| Board of Directors | 1961 – 1991 |
| Board of Directors | 2006 – 2009 |
| Board of Directors | 1961 – 1996 |
| Board of Directors | 1961 – 2005 |
| Board of Directors | 2012 – 2013 |
| Board of Directors | 1997 – 2006 |
| Chairman | 2016 – 2022 |
| Board of Directors | 2009 – 2012 |
| Board of Directors | 2017 – 2022 |
| Chairman | 2012 – 2016 |
| Board of Directors | 2013 – 2017 |
| Board of Directors | 1961 – 2003 |
| Board of Directors | 1961 – 1991 |
| Board of Directors | 2005 – 2009 |