| Year | Protected | Not Protected | Protected % |
| 1998 | 3 | 7 | 30.00 |
| 1999 | 10 | 7 | 58.82 |
| 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 | 28 | 13 | 68.29 |
| 2006 | 22 | 19 | 53.66 |
| 2007 | 28 | 3 | 90.32 |
| 2008 | 2 | 29 | 6.45 |
| 2009 | 1 | 31 | 3.13 |
| 2010 | 0 | 32 | 0.00 |
| 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 |
| 2017 | 0 | 36 | 0.00 |
| Totals | 256 | 378 | 40.38 |