| Year | Protected | Not Protected | Protected % |
| 1998 | 10 | 0 | 100.00 |
| 1999 | 17 | 0 | 100.00 |
| 2000 | 21 | 0 | 100.00 |
| 2001 | 28 | 0 | 100.00 |
| 2002 | 34 | 0 | 100.00 |
| 2003 | 39 | 0 | 100.00 |
| 2004 | 40 | 0 | 100.00 |
| 2005 | 41 | 0 | 100.00 |
| 2006 | 35 | 6 | 85.37 |
| 2007 | 31 | 0 | 100.00 |
| 2008 | 30 | 1 | 96.77 |
| 2009 | 26 | 6 | 81.25 |
| 2010 | 32 | 0 | 100.00 |
| 2011 | 29 | 3 | 90.63 |
| 2012 | 21 | 12 | 63.64 |
| 2013 | 16 | 17 | 48.48 |
| 2014 | 2 | 32 | 5.88 |
| 2015 | 0 | 34 | 0.00 |
| 2016 | 0 | 35 | 0.00 |
| 2017 | 0 | 36 | 0.00 |
| Totals | 452 | 182 | 71.29 |