| Current (2) |
| Chairman | 2019 |
| Board of Directors | 2013 |
| Former (23) |
| Board of Directors | 1983 – 1995 |
| Board of Directors | 2004 – 2007 |
| Board of Directors | 1983 – 1989 |
| Board of Directors | 1983 – 1992 |
| Board of Directors | 1983 – 1992 |
| Board of Directors | 1983 – 1989 |
| Chairman | 2001 – 2002 |
| Chairman | 2010 – 2013 |
| Chairman | 2013 – 2019 |
| Board of Directors | 1983 – 1990 |
| Chairman | 1995 – 1998 |
| Chairman | 1998 – 2001 |
| Board of Directors | 1983 – 1992 |
| Board of Directors | 1983 – 2003 |
| Chairman | 1983 – 1993 |
| Board of Directors | 1983 – 1991 |
| Board of Directors | 1983 – 1995 |
| Board of Directors | 1983 – 1993 |
| Board of Directors | 1983 – 1989 |
| Chairman | 2004 – 2010 |
| Board of Directors | 2007 – 2013 |
| Chairman | 1983 – 1989 |
| Board of Directors | 2003 – 2004 |