Year Years 1960 1.813 1961 3.232 1962 3.175 1963 2.881 1964 3.23 1965 3.237 1966 3.701 1967 3.876 1968 5.06 1969 5.471 1970 4.286 1971 3.883 1972 3.163 1973 3.585 1974 2.953 1975 2.926 1976 2.75 1977 2.857 1978 2.627 1979 2.747 1980 4.159 1981 4.41 1982 4.786 1983 3.95 1984 4.326 1985 4.298 1986 4.231 1987 3.508 1988 2.168 1989 2.217 1990 0.6457 1991 1.123 1992 1.091 1993 1.387 1994 1.216 1995 0.7052 1996 0.5781 1997 1.046 1998 2.567 1999 2.558 2000 2.588 2001 1.547 2002 1.493 2003 1.62