Year Percent 1960 1.89267 1961 1.93225 1962 1.94603 1963 1.90081 1964 1.78125 1965 1.61509 1966 1.43198 1967 1.27535 1968 1.17085 1969 1.13661 1970 1.15169 1971 1.18318 1972 1.19812 1973 1.19004 1974 1.14723 1975 1.08184 1976 1.00276 1977 0.93779 1978 0.91037 1979 0.93381 1980 0.98661 1981 1.01534 1982 1.00849 1983 0.99835 1984 0.9849 1985 0.9467 1986 0.98269 1987 0.96512 1988 0.65736 1989 -0.03113 1990 -0.9639 1991 -2.0786 1992 -3.0766 1993 -3.63081 1994 -3.46398 1995 -2.69772 1996 -1.66146 1997 -0.74201 1998 -0.05187 1999 0.22992 2000 0.20165 2001 0.12146 2002 0.11986 2003 0.09106 2004 0.05396 2005 0.00643 2006 -0.05454 2007 -0.14478 2008 -0.27598 2009 -0.45373 2010 -0.65546 2011 -0.89649 2012 -1.10849 2013 -1.19124 2014 -1.08764 2015 -0.846 2016 -0.54291 2017 -0.27902