| Year | Protected | Not Protected | Protected % |
| 1998 | 6 | 4 | 60.00 |
| 1999 | 16 | 1 | 94.12 |
| 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 | 36 | 5 | 87.80 |
| 2007 | 30 | 1 | 96.77 |
| 2008 | 22 | 9 | 70.97 |
| 2009 | 1 | 31 | 3.13 |
| 2010 | 6 | 26 | 18.75 |
| 2011 | 0 | 32 | 0.00 |
| 2012 | 0 | 33 | 0.00 |
| 2013 | 0 | 33 | 0.00 |
| 2014 | 0 | 34 | 0.00 |
| 2015 | 0 | 34 | 0.00 |
| 2016 | 0 | 35 | 0.00 |
| Totals | 320 | 278 | 53.51 |