| Year | Protected | Not Protected | Protected % |
| 1998 | 2 | 8 | 20.00 |
| 1999 | 3 | 14 | 17.65 |
| 2000 | 11 | 10 | 52.38 |
| 2001 | 19 | 9 | 67.86 |
| 2002 | 30 | 4 | 88.24 |
| 2003 | 38 | 1 | 97.44 |
| 2004 | 5 | 35 | 12.50 |
| 2005 | 38 | 3 | 92.68 |
| 2006 | 37 | 4 | 90.24 |
| 2007 | 30 | 1 | 96.77 |
| 2008 | 27 | 4 | 87.10 |
| 2009 | 7 | 25 | 21.88 |
| 2010 | 3 | 29 | 9.38 |
| 2011 | 30 | 2 | 93.75 |
| 2012 | 32 | 1 | 96.97 |
| 2013 | 19 | 14 | 57.58 |
| 2014 | 0 | 34 | 0.00 |
| 2015 | 0 | 34 | 0.00 |
| 2016 | 0 | 35 | 0.00 |
| 2017 | 0 | 36 | 0.00 |
| Totals | 331 | 303 | 52.21 |