Year Years 1963 5.34 1964 4.742 1965 4.086 1966 3.113 1967 1.938 1968 1.8 1969 1.865 1970 2.654 1971 2.464 1972 3.156 1973 2.589 1974 1.872 1975 1.201 1976 1.063 1977 1.049 1978 1.002 1979 0.2553 1980 -1.664 1981 -1.772 1982 -2.619 1983 -2.133 1984 -2.059 1985 -2.049 1986 -1.827 1987 -0.7452 1988 -0.5257 1989 0.5284 1990 1.774 1991 1.624 1992 2.049 1993 1.943 1994 2.184 1995 2.608 1996 2.451 1997 1.407 1998 1.545 1999 0.6794 2000 0.168 2001 0.3582 2002 0.00705 2003 -0.3392