| Current (2) |
| Chairman | 2020 |
| Board of Directors | 2019 |
| Former (18) |
| Board of Directors | 1997 – 2004 |
| Chairman | 2006 – 2008 |
| Chairman | 2008 – 2010 |
| Board of Directors | 1998 – 2003 |
| Board of Directors | 2013 – 2015 |
| Chairman | 2010 – 2012 |
| Chairman | 2015 – 2015 |
| Board of Directors | 2015 – 2018 |
| Chairman | 2004 – 2006 |
| Board of Directors | 1997 – 1998 |
| Board of Directors | 1984 – 1997 |
| Board of Directors | 2018 – 2022 |
| Board of Directors | 1984 – 1992 |
| Board of Directors | 2007 – 2013 |
| Board of Directors | 2016 – 2019 |
| Board of Directors | 2003 – 2006 |
| Board of Directors | 2006 – 2007 |
| Chairman | 2018 – 2020 |