| date | taxLabel | obsValue |
|---|---|---|
| 2002 | Environment | 6.8 |
| 2003 | Environment | 6.85 |
| 2004 | Environment | 6.8 |
| 2005 | Environment | 6.62 |
| 2006 | Environment | 6.38 |
| 2007 | Environment | 6.17 |
| 2008 | Environment | 6.03 |
| 2009 | Environment | 6.34 |
| 2010 | Environment | 6.37 |
| 2011 | Environment | 6.38 |
| 2012 | Environment | 6.35 |
| 2013 | Environment | 6.34 |
| 2014 | Environment | 6.34 |
| 2015 | Environment | 6.32 |
| 2002 | Labour | 50.8 |
| 2003 | Labour | 50.9 |
| 2004 | Labour | 50.2 |
| 2005 | Labour | 49.6 |
| 2006 | Labour | 48.8 |
| 2007 | Labour | 48.6 |
| 2008 | Labour | 49.9 |
| 2009 | Labour | 52.0 |
| 2010 | Labour | 51.3 |
| 2011 | Labour | 50.9 |
| 2012 | Labour | 51.0 |
| 2016 | Environment | 6.29 |
| 2013 | Labour | 50.6 |
| 2014 | Labour | 50.3 |
| 2015 | Labour | 49.7 |
| 2016 | Labour | 49.8 |