| Chairman | 2017 – 2018 |
| Board of Directors | 2005 – 2010 |
| Board of Directors | 2003 – 2004 |
| Chairman | 2003 – 2005 |
| Board of Directors | 1971 – 2003 |
| Chairman | 1971 – 1989 |
| Board of Directors | 1971 – 2003 |
| Chairman | 2015 – 2017 |
| Board of Directors | 2004 – 2005 |
| Chairman | 2005 – 2006 |
| Board of Directors | 2017 – 2018 |
| Board of Directors | 1971 – 1989 |
| Board of Directors | 2005 – 2018 |
| Board of Directors | 2003 – 2004 |
| Chairman | 2013 – 2015 |
| Chairman | 2018 – 2018 |
| Chairman | 2006 – 2013 |
| Board of Directors | 2010 – 2013 |
| Board of Directors | 2013 – 2017 |
| Board of Directors | 1971 – 2003 |
| Board of Directors | 1971 – 1992 |
| Board of Directors | 2018 – 2018 |