Year Years 1970 5.254 1971 5.084 1972 4.673 1973 4.963 1974 4.982 1975 3.602 1976 3.148 1977 2.535 1978 2.839 1979 2.375 1980 1.502 1981 0.6889 1982 0.3035 1983 0.5967 1984 0.9152 1985 1.55 1986 2.428 1987 2.331 1988 1.937 1989 1.248 1990 0.7816 1991 1.07 1992 0.8237 1993 0.3137 1994 0.0055 1995 0.4185 1996 -0.08692 1997 -0.1907 1998 0.01466 1999 0.2391 2000 0.9905 2001 0.7831 2002 1.18 2003 1.698 2004 1.61