Year Percent 1990 1.69912 1991 1.57528 1992 1.25005 1993 1.26928 1994 1.29763 1995 1.70248 1996 1.67908 1997 1.59376 1998 1.54932 1999 1.47946 2000 1.32551 2001 1.18439 2002 1.32487 2003 1.13526 2004 1.07741 2005 1.03785 2006 1.01462 2007 0.9863 2008 0.96327 2009 0.95198 2010 0.95058 2011 0.91558 2012 0.91473 2013 0.91698 2014 0.86613 2015 0.86799 2016 0.8615 2017 0.85597 2018 0.8563 2019 0.86002 2020 0.87135