| Current (2) |
| Board of Directors | 2015 |
| Board of Directors | 2018 |
| Former (13) |
| Chairman | 2010 – 2018 |
| Board of Directors | 2006 – 2015 |
| Board of Directors | 2001 – 2006 |
| Board of Directors | 1991 – 1992 |
| Chairman | 1991 – 2002 |
| Board of Directors | 1991 – 2002 |
| Board of Directors | 1991 – 1997 |
| Board of Directors | 2004 – 2009 |
| Chairman | 1991 – 1992 |
| Chairman | 2002 – 2010 |
| Board of Directors | 2004 – 2013 |
| Board of Directors | 2002 – 2004 |
| Board of Directors | 2015 – 2017 |