Year Years 1960 4.032 1961 4.083 1962 3.263 1963 3.403 1964 2.678 1965 2.877 1966 2.004 1967 2.423 1968 2.054 1969 1.581 1970 1.766 1971 1.826 1972 1.948 1973 2.166 1974 2.118 1975 2.29 1976 2.789 1977 3.106 1978 3.095 1979 2.94 1980 3.099 1981 3.097 1982 2.485 1983 1.855 1984 1.548 1985 0.2121 1986 -0.0493 1987 -0.5291 1988 -0.2349 1989 0.03934 1990 -0.2596 1991 -0.5902 1992 -0.4478 1993 -0.5376 1994 0.2745 1995 1.124 1996 0.9847 1997 1.69 1998 0.7232 1999 0.8885 2000 1.774 2001 1.348 2002 1.335 2003 1.256 2004 1.815