Year Percent 1990 1.00465 1991 0.92207 1992 0.88986 1993 0.85827 1994 0.83102 1995 1.14524 1996 1.10723 1997 1.06861 1998 0.60788 1999 0.58947 2000 0.58327 2001 0.56886 2002 0.555 2003 0.68186 2004 0.73972 2005 0.72237 2006 0.72046 2007 0.70826 2008 0.67883 2009 0.64436 2010 0.61345 2011 0.61661 2012 0.61187 2013 0.55348 2014 0.49073 2015 0.47709 2016 0.56981 2017 0.55266 2018 0.51785 2019 0.52284 2020 0.54676