| Current (2) |
| Chairman | 2020 |
| Board of Directors | 2010 |
| Former (16) |
| Chairman | 1920 – 1992 |
| Board of Directors | 2005 – 2010 |
| Board of Directors | 2005 – 2008 |
| Board of Directors | 2006 – 2009 |
| Board of Directors | 1998 – 2000 |
| Board of Directors | 1920 – 1998 |
| Chairman | 2005 – 2009 |
| Board of Directors | 1998 – 2000 |
| Board of Directors | 1920 – 1993 |
| Chairman | 2009 – 2020 |
| Board of Directors | 1920 – 1992 |
| Board of Directors | 1998 – 1998 |
| Board of Directors | 1920 – 1998 |
| Chairman | 1920 – 1993 |
| Board of Directors | 2000 – 2001 |
| Board of Directors | 2001 – 2008 |