Year	US Dollars adjusted for inflation)
1960	497.8
1961	452.1
1962	494.6
1963	498.5
1964	565.5
1965	556
1966	571.6
1967	583.7
1968	615.5
1969	613.2
1970	576.1
1971	558.6
1972	581
1973	572.4
1974	564.5
1975	580.4
1976	600.8
1977	581.6
1978	570.5
1979	571.2
1980	570.5
1981	554.9
1982	538.2
1983	512.4
1984	510
1985	502.2
1986	495.8
1987	495.7
1988	495.8
1989	493.5
1990	498.3
1991	515.1
1992	498.9
1993	492.8
1994	474.4
1995	484.7
1996	491.3
1997	773.1
1998	800.8
1999	819.1
2000	816.7
2001	848.2
2002	898.7
2003	911.9