Year Years 1961 0.3497 1962 0.6561 1963 1.312 1964 1.149 1965 0.5918 1966 0.6969 1967 1.057 1968 0.8161 1969 1.281 1970 1.709 1971 1.507 1972 1.777 1973 1.783 1974 1.971 1975 2.478 1976 2.938 1977 3.259 1978 3.896 1979 4.524 1980 4.977 1981 5.271 1982 4.865 1983 4.403 1984 3.967 1985 3.541 1986 2.904 1987 2.214 1988 1.844 1989 1.341 1990 0.5185 1991 0.00224 1992 0.1211 1993 0.6021 1994 0.5755 1995 0.6291 1996 0.882 1997 0.7933 1998 0.1763 1999 -0.2135 2000 -0.2888 2001 -0.2041 2002 -0.6747 2003 -0.9348