| Current (2) |
| Chairman | 2019 |
| Board of Directors | 2019 |
| Former (15) |
| Board of Directors | 1984 – 1993 |
| Board of Directors | 2011 – 2015 |
| Chairman | 2007 – 2011 |
| Chairman | 2005 – 2007 |
| Board of Directors | 2013 – 2016 |
| Chairman | 2011 – 2016 |
| Board of Directors | 2011 – 2015 |
| Chairman | 2016 – 2019 |
| Board of Directors | 2015 – 2016 |
| Board of Directors | 1984 – 1997 |
| Board of Directors | 1984 – 1995 |
| Board of Directors | 1984 – 2005 |
| Board of Directors | 2015 – 2016 |
| Board of Directors | 2016 – 2019 |
| Board of Directors | 2011 – 2013 |