| Year | Protected | Not Protected | Protected % |
| 2015 | 0 | 34 | 0.00 |
| 2006 | 30 | 6 | 83.33 |
| 2004 | 18 | 26 | 40.91 |
| 2014 | 0 | 34 | 0.00 |
| 2009 | 13 | 21 | 38.24 |
| 2007 | 26 | 7 | 78.79 |
| 2013 | 8 | 26 | 23.53 |
| 2008 | 23 | 11 | 67.65 |
| 1998 | 0 | 15 | 0.00 |
| 2012 | 9 | 25 | 26.47 |
| 2001 | 24 | 9 | 72.73 |
| 2011 | 14 | 20 | 41.18 |
| 2016 | 0 | 34 | 0.00 |
| 2003 | 31 | 11 | 73.81 |
| 2010 | 18 | 15 | 54.55 |
| 2002 | 27 | 11 | 71.05 |
| 2000 | 1 | 27 | 3.57 |
| 2005 | 22 | 23 | 48.89 |
| 1999 | 0 | 22 | 0.00 |
| Totals | 264 | 377 | 41.19 |