Year Percent 1960 -0.28797 1961 0.01135 1962 0.79817 1963 0.38964 1964 0.25407 1965 1.07759 1966 0.99047 1967 2.72166 1968 1.31252 1969 3.25843 1970 3.90751 1971 3.40709 1972 2.6796 1973 1.75416 1974 0.89649 1975 0.53561 1976 0.43947 1977 0.52776 1978 0.23296 1979 0.14098 1980 0.2593 1981 0.34467 1982 0.27653 1983 0.17577 1984 0.43527 1985 0.29759 1986 0.434 1987 0.30709 1988 0.26061 1989 0.9158 1990 -0.0135 1991 0.05029 1992 0.1077 1993 0.10485 1994 0.06952 1995 0.056