Year Percent 1990 0.98547 1991 0.95685 1992 1.03287 1993 1.00173 1994 0.97205 1995 1.57891 1996 1.37947 1997 1.3549 1998 1.3284 1999 1.28966 2000 1.22842 2001 0.93751 2002 0.91538 2003 0.88815 2004 0.854 2005 0.81955 2007 0.75502 2008 0.73056 2009 0.70037 2010 0.67099 2011 0.65127 2012 0.63635 2013 0.62478 2014 0.6129 2015 0.60066 2016 0.58778 2017 0.57419 2018 0.56039 2019 0 2020 0.53705