| Year | Protected | Not Protected | Protected % |
| 2015 | 0 | 34 | 0.00 |
| 2006 | 32 | 4 | 88.89 |
| 2004 | 44 | 0 | 100.00 |
| 2014 | 0 | 34 | 0.00 |
| 2009 | 34 | 0 | 100.00 |
| 2007 | 32 | 1 | 96.97 |
| 2013 | 32 | 2 | 94.12 |
| 2008 | 34 | 0 | 100.00 |
| 1998 | 12 | 3 | 80.00 |
| 2012 | 5 | 29 | 14.71 |
| 2001 | 33 | 0 | 100.00 |
| 2011 | 5 | 29 | 14.71 |
| 2016 | 0 | 34 | 0.00 |
| 2003 | 42 | 0 | 100.00 |
| 2010 | 29 | 4 | 87.88 |
| 2002 | 38 | 0 | 100.00 |
| 2000 | 28 | 0 | 100.00 |
| 2005 | 43 | 2 | 95.56 |
| 1999 | 18 | 4 | 81.82 |
| Totals | 461 | 180 | 71.92 |