Year Percent 1990 1.38649 1991 1.34239 1992 1.30464 1993 1.2617 1994 1.22289 1995 1.9852 1996 1.91405 1997 1.50879 1998 1.48246 1999 1.45724 2000 1.43311 2001 1.41035 2002 1.3894 2003 1.37082 2004 1.35501 2005 1.34198 2006 1.34341 2007 1.31563 2008 1.28708 2009 1.25437 2010 1.22793 2011 1.20252 2012 1.17233 2013 1.17031 2014 1.16475 2015 1.15983 2016 1.14833 2017 1.14873 2018 1.13676 2019 1.13192 2020 1.18035