Year Years 1960 2.664 1961 2.069 1962 1.948 1963 2.176 1964 2.454 1965 2.21 1966 1.342 1967 0.6354 1968 1.382 1969 1.443 1970 2.661 1971 1.692 1972 1.328 1973 1.777 1974 1.885 1975 2.025 1976 2.951 1977 3.289 1978 2.761 1979 2.273 1980 1.282 1981 2.067 1982 1.585 1983 0.1765 1984 -0.7497 1985 -1.329 1986 -1.635 1987 -1.917 1988 -1.523 1989 -2.362 1990 -1.624 1991 -0.725 1992 0.01523 1993 0.42 1994 -0.03922 1995 0.3605 1996 -0.3053 1997 -0.0102 1998 -0.516 1999 -0.1064 2000 -0.2168 2001 -0.7634 2002 -2.091 2003 -2.58 2004 -0.8316