Year Percent 1990 1.88572 1991 1.85794 1992 1.83865 1993 1.85594 1994 1.79364 1995 1.8541 1996 1.80958 1997 1.7559 1998 1.76615 1999 1.79109 2000 1.64204 2001 1.6109 2002 1.64801 2003 1.67359 2004 1.65817 2005 1.65109 2007 1.58587 2008 1.57256 2009 1.51819 2010 1.51949 2011 1.47072 2012 1.47947 2013 1.47922 2014 1.44777 2015 1.46068 2016 1.46024 2017 1.26558 2018 1.27366 2019 1.26189 2020 1.30601