Year Percent 1981 1.03869 1982 1.02201 1983 1.02097 1984 1.01696 1985 1.01965 1986 1.01325 1987 0.99869 1988 1.0085 1989 1.00803 1990 0.99768 1998 1.02404 1999 1.02879 2001 1.03037 2002 1.02637 2003 1.02473 2004 1.02553 2005 1.03008 2006 1.02784 2007 1.02342 2008 1.02144 2009 1.01826 2013 1.01821 2015 1.00883