| Current (2) |
| Board of Directors | 2019 |
| Chairman | 2022 |
| Former (23) |
| Chairman | 2013 – 2022 |
| Board of Directors | 2007 – 2009 |
| Board of Directors | 1961 – 1991 |
| Board of Directors | 1961 – 1993 |
| Board of Directors | 1961 – 1989 |
| Board of Directors | 1961 – 2001 |
| Board of Directors | 2012 – 2019 |
| Chairman | 1996 – 2000 |
| Board of Directors | 2001 – 2007 |
| Board of Directors | 1961 – 1988 |
| Board of Directors | 2003 – 2007 |
| Chairman | 2010 – 2013 |
| Board of Directors | 1999 – 2003 |
| Board of Directors | 1961 – 1997 |
| Board of Directors | 2003 – 2007 |
| Board of Directors | 2002 – 2003 |
| Board of Directors | 1961 – 1996 |
| Board of Directors | 2003 – 2010 |
| Board of Directors | 2010 – 2012 |
| Board of Directors | 1961 – 1999 |
| Board of Directors | 1999 – 2003 |
| Chairman | 2009 – 2010 |
| Chairman | 2000 – 2003 |