Year % 1995 35.27 1996 45.11 1997 34.74 1998 34.71 1999 43.51 2000 42.55 2001 43.06 2002 42.96 2003 44.09 2004 38.22 2005 36.95 2006 43.69 2007 42.76 2008 39.35 2009 37.83 2010 42.97 2011 42.94 2012 43.27 2013 43.54 2014 40.5 2015 41.58 2016 43.61 2017 49.81