Year % 1995 35.27 1996 41.91 1997 34.74 1998 34.71 1999 40.58 2000 39.9 2001 40.12 2002 40.04 2003 41.1 2004 35.46 2005 36.02 2006 40.75 2007 39.84 2008 37.09 2009 36.07 2010 40.03 2011 39.99 2012 40.32 2013 40.65 2014 38.61 2015 40.33 2016 42.21 2017 46.74