Year % 1995 43.77 1997 39 1998 42.83 1999 38.89 2000 35.69 2001 31.4 2002 36.87 2003 35.68 2004 33.45 2005 36.81 2006 36.8 2007 31.55 2008 35.7 2009 36.95 2010 35.7 2011 36.91 2012 37.09 2013 33.83 2014 33.82 2015 32.79 2016 32.79 2017 36.58