Year Percent 1960 0.43654 1961 -0.00391 1962 -0.44441 1963 -0.86905 1964 -1.18462 1965 -1.44439 1966 -1.75465 1967 -2.04315 1968 -2.08576 1969 -1.88833 1970 -1.43556 1971 -0.87268 1972 -0.38054 1973 -0.02256 1974 0.03384 1975 -0.12414 1976 -0.28951 1977 -0.4677 1978 -0.54538 1979 -0.56448 1980 -0.57 1981 -0.54301 1982 -0.4992 1983 -0.5158 1984 -0.58466 1985 -0.66661 1986 -0.75499 1987 -0.83326 1988 -0.73789 1989 -0.4762 1990 -0.04407 1991 0.4374 1992 0.84493 1993 1.16578 1994 1.25152 1995 1.21506 1996 1.11751 1997 1.08464 1998 1.06849 1999 1.13754 2000 1.21955 2001 1.34847 2002 1.4056 2003 1.41572 2004 1.39595 2005 1.32532 2006 1.2247 2007 1.15767 2008 1.09675 2009 1.09468 2010 1.09254 2011 1.08458 2012 1.11859 2013 1.09305 2014 1.06635 2015 1.01642 2016 0.97701 2017 0.9513