Year Percent 1990 1.22438 1991 1.2327 1992 1.2048 1993 1.22133 1994 1.16844 1995 1.43761 1996 1.44878 1997 1.18613 1998 1.17415 1999 1.03827 2000 1.03851 2001 0.88812 2002 0.87126 2003 0.86192 2004 0.99498 2005 0.98853 2006 0.97213 2007 0.83308 2008 0.82482 2009 0.6044 2010 0.59866 2011 0.53665 2012 0.52059 2013 0.50868 2014 0.5062 2015 0.47476 2016 0.48916 2017 0.45567 2018 0.4922 2019 0.47183 2020 0.49587