| 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 | 2 | 32 | 5.88 |
| 2003 | 0 | 39 | 0.00 |
| 2004 | 26 | 14 | 65.00 |
| 2005 | 41 | 0 | 100.00 |
| 2006 | 37 | 4 | 90.24 |
| 2007 | 31 | 0 | 100.00 |
| 2008 | 31 | 0 | 100.00 |
| 2009 | 32 | 0 | 100.00 |
| 2010 | 10 | 22 | 31.25 |
| 2011 | 21 | 11 | 65.63 |
| 2012 | 27 | 6 | 81.82 |
| 2013 | 31 | 2 | 93.94 |
| 2014 | 34 | 0 | 100.00 |
| 2015 | 31 | 3 | 91.18 |
| 2016 | 26 | 9 | 74.29 |
| 2017 | 0 | 36 | 0.00 |
| 2018 | 0 | 37 | 0.00 |
| 2019 | 0 | 38 | 0.00 |
| Totals | 380 | 329 | 53.60 |