Year Percent 1961 0.22603 1962 -2.83623 1963 -0.91146 1964 1.02397 1965 -1.4898 1966 -0.01023 1967 -4.00711 1968 3.26371 1969 -9.25169 1970 5.38332 1971 -3.12029 1972 3.17049 1973 -8.40353 1974 1.20855 1975 4.61949 1976 6.15774 1977 -5.02444 1978 -6.22578 1979 4.39259 1980 -5.80948 1981 2.18819 1982 4.75133 1983 -8.12658 1984 0.63088 1985 0.17113 1986 0.00704 1987 2.89738 1988 -3.58642 1989 0.84765 1990 -3.65995 1991 -0.52541 1992 -1.7843 1993 -1.66819 1994 -2.83637 1995 2.53944 1996 -0.57363 1997 0.62961 1998 3.40406 1999 3.85064 2000 0.701 2001 1.9965 2002 -1.88521 2003 3.94262 2004 3.11717 2005 2.85024 2006 -0.24695 2007 2.13866 2008 0.87551 2009 -0.40823 2010 1.23284 2011 -1.18196 2012 1.34363 2013 0.40165 2014 1.02862 2015 3.39418 2016 3.73161 2017 3.8298