| Current (2) |
| Chairman | 2009 |
| Board of Directors | 1981 |
| Former (12) |
| Board of Directors | 2011 – 2019 |
| Board of Directors | 2015 – 2021 |
| Board of Directors | 1981 – 2009 |
| Board of Directors | 1981 – 1999 |
| Board of Directors | 1981 – 1995 |
| Board of Directors | 2002 – 2021 |
| Board of Directors | 2003 – 2019 |
| Board of Directors | 1999 – 2003 |
| Board of Directors | 2007 – 2011 |
| Board of Directors | 2009 – 2014 |
| Board of Directors | 2003 – 2003 |
| Board of Directors | 2015 – 2020 |