| Year | Protected | Not Protected | Protected % |
| 2015 | 0 | 34 | 0.00 |
| 2006 | 1 | 35 | 2.78 |
| 2004 | 13 | 31 | 29.55 |
| 2014 | 0 | 34 | 0.00 |
| 2009 | 0 | 34 | 0.00 |
| 2007 | 1 | 32 | 3.03 |
| 2013 | 2 | 32 | 5.88 |
| 2008 | 0 | 34 | 0.00 |
| 1998 | 0 | 15 | 0.00 |
| 2012 | 8 | 26 | 23.53 |
| 2001 | 6 | 27 | 18.18 |
| 2011 | 0 | 34 | 0.00 |
| 2016 | 0 | 34 | 0.00 |
| 2003 | 23 | 19 | 54.76 |
| 2010 | 3 | 30 | 9.09 |
| 2002 | 9 | 29 | 23.68 |
| 2000 | 0 | 28 | 0.00 |
| 2005 | 16 | 29 | 35.56 |
| 1999 | 0 | 22 | 0.00 |
| Totals | 82 | 559 | 12.79 |