Year Percent 1994-01-01 13.65517364902050 1995-01-01 13.11346042457990 1996-01-01 11.32877053674870 1997-01-01 11.87454948060540 1998-01-01 12.60392115860270 1999-01-01 16.35216523495850 2000-01-01 18.75749916420760 2001-01-01 19.30597272991640 2002-01-01 18.67132798835690 2003-01-01 17.55514839597380 2004-01-01 18.22449476194080 2005-01-01 16.25893357071960 2006-01-01 13.37261753896820 2007-01-01 11.14480733341770 2008-01-01 9.51219399277086 2009-01-01 12.01790786952710 2010-01-01 14.38102628557470 2011-01-01 13.61757908895200 2012-01-01 13.96334761620580 2013-01-01 14.22133053525390 2014-01-01 13.18427678528960 2015-01-01 11.48227072608140 2016-01-01 9.67168875524164 2017-01-01 8.13096551932692