Year Years 1960 -0.4482 1961 -0.1085 1962 0.04231 1963 0.2937 1964 1.281 1965 2.078 1966 2.112 1967 2.618 1968 3.02 1969 2.912 1970 4.4 1971 4.339 1972 4.616 1973 3.886 1974 3.231 1975 3.048 1976 2.721 1977 2.989 1978 2.648 1979 3.232 1980 2.567 1981 2.777 1982 2.797 1983 3.126 1984 3.625 1985 3.528 1986 3.869 1987 3.878 1988 4.249 1989 3.697 1990 3.283 1991 3.273 1992 2.953 1993 2.702 1994 2.535 1995 2.521 1996 1.91 1997 1.493 1998 1.262 1999 1.402 2000 1.207 2001 0.833 2002 0.9598 2003 1.221 2004 1.291