| Year | Protected | Not Protected | Protected % |
| 1998 | 0 | 10 | 0.00 |
| 1999 | 0 | 17 | 0.00 |
| 2000 | 20 | 1 | 95.24 |
| 2001 | 17 | 11 | 60.71 |
| 2002 | 31 | 3 | 91.18 |
| 2003 | 37 | 2 | 94.87 |
| 2004 | 40 | 0 | 100.00 |
| 2005 | 41 | 0 | 100.00 |
| 2006 | 35 | 6 | 85.37 |
| 2007 | 31 | 0 | 100.00 |
| 2008 | 31 | 0 | 100.00 |
| 2009 | 32 | 0 | 100.00 |
| 2010 | 28 | 4 | 87.50 |
| 2011 | 18 | 14 | 56.25 |
| 2012 | 28 | 5 | 84.85 |
| 2013 | 27 | 6 | 81.82 |
| 2014 | 28 | 6 | 82.35 |
| 2015 | 0 | 34 | 0.00 |
| 2016 | 0 | 35 | 0.00 |
| 2017 | 0 | 36 | 0.00 |
| 2018 | 0 | 37 | 0.00 |
| 2019 | 0 | 38 | 0.00 |
| 2020 | 0 | 39 | 0.00 |
| Totals | 444 | 304 | 59.36 |