Year Percent 1990 1.78505 1991 1.72485 1992 1.52065 1993 1.46743 1994 1.44335 1995 1.72562 1996 1.56251 1997 1.52812 1998 1.51954 1999 1.5216 2000 1.36671 2001 1.29053 2002 1.05809 2003 1.06328 2004 0.9356 2005 0.92072 2006 0.85192 2007 0.81807 2008 0.81354 2009 0.68038 2010 0.67239 2011 0.65044 2012 0.94533 2013 0.94437 2014 0.93895 2015 0.94205 2016 0.97106 2017 1.0362 2018 1.06967 2019 1.03124 2020 1.03587