Year % 1995 43.77 1997 39 1998 42.83 1999 34.65 2000 33.73 2001 27.52 2002 37.16 2003 34.23 2004 36.06 2005 32.7 2006 32.7 2007 30.56 2008 32.14 2009 32.99 2010 42.23 2011 34.86 2012 33.08 2013 31.28 2014 31.62 2015 31.3 2016 33.35 2017 36.58