| Year | Protected | Not Protected | Protected % |
| 1998 | 0 | 10 | 0.00 |
| 1999 | 6 | 11 | 35.29 |
| 2000 | 20 | 1 | 95.24 |
| 2001 | 26 | 2 | 92.86 |
| 2002 | 31 | 3 | 91.18 |
| 2003 | 25 | 14 | 64.10 |
| 2004 | 1 | 39 | 2.50 |
| 2005 | 41 | 0 | 100.00 |
| 2006 | 24 | 17 | 58.54 |
| 2007 | 9 | 22 | 29.03 |
| 2008 | 20 | 11 | 64.52 |
| 2009 | 13 | 19 | 40.63 |
| 2010 | 4 | 28 | 12.50 |
| 2011 | 29 | 3 | 90.63 |
| 2012 | 33 | 0 | 100.00 |
| 2013 | 33 | 0 | 100.00 |
| 2014 | 34 | 0 | 100.00 |
| 2015 | 34 | 0 | 100.00 |
| 2016 | 29 | 6 | 82.86 |
| 2017 | 32 | 4 | 88.89 |
| 2018 | 21 | 16 | 56.76 |
| 2019 | 0 | 38 | 0.00 |
| 2020 | 0 | 39 | 0.00 |
| 2021 | 0 | 30 | 0.00 |
| Totals | 465 | 313 | 59.77 |