Year Percent 1961 -0.95114 1962 2.85805 1963 0.72751 1964 2.48825 1965 5.97125 1966 2.37178 1967 2.92546 1968 3.50467 1969 -2.27509 1970 0.60786 1971 0.96724 1972 2.68027 1973 4.71328 1974 -4.14181 1975 -0.9141 1976 7.17336 1977 7.03642 1978 6.65699 1979 1.47868 1980 -2.3864 1981 -0.56615 1982 -4.35955 1983 -3.89052 1984 1.24316 1985 1.11451 1986 -2.22282 1987 2.95803 1988 1.59982 1989 1.34015 1990 -2.75516 1991 0.32404 1992 2.64778 1993 3.25948 1994 -4.03738 1995 1.21169 1996 0.79171 1997 2.18931 1998 0.19039 1999 -4.43898 2000 3.04034 2001 0.13284 2002 1.1829 2003 2.01038 2004 3.72059 2005 3.61592 2006 4.19358 2007 3.89364 2008 2.05121 2009 -4.40318 2010 1.7089 2011 1.88592 2012 2.24281 2013 0.98525 2014 1.28651 2015 2.08315 2016 2.02116 2017 3.06396