| Year | Protected | Not Protected | Protected % |
| 1998 | 0 | 10 | 0.00 |
| 1999 | 0 | 17 | 0.00 |
| 2000 | 0 | 21 | 0.00 |
| 2001 | 0 | 28 | 0.00 |
| 2002 | 3 | 31 | 8.82 |
| 2003 | 36 | 3 | 92.31 |
| 2004 | 15 | 25 | 37.50 |
| 2005 | 12 | 29 | 29.27 |
| 2006 | 14 | 27 | 34.15 |
| 2007 | 14 | 17 | 45.16 |
| 2008 | 24 | 7 | 77.42 |
| 2009 | 11 | 21 | 34.38 |
| 2010 | 22 | 10 | 68.75 |
| 2011 | 8 | 24 | 25.00 |
| 2012 | 0 | 33 | 0.00 |
| 2013 | 4 | 29 | 12.12 |
| 2014 | 3 | 31 | 8.82 |
| 2015 | 0 | 34 | 0.00 |
| 2016 | 0 | 35 | 0.00 |
| 2017 | 0 | 36 | 0.00 |
| 2018 | 0 | 37 | 0.00 |
| Totals | 166 | 505 | 24.74 |