Year	US Dollars adjusted for inflation)
1970	2537
1971	2615
1972	3242
1973	2844
1974	2562
1975	2335
1976	2433
1977	2507
1978	3004
1979	2942
1980	2840
1981	3328
1982	3530
1983	3737
1984	3950
1985	3931
1986	4148
1987	4214
1988	4514
1989	4800
1990	5560
1991	5386
1992	6073
1993	6495
1994	6269
1995	6649
1996	6781
1997	6463
1998	6433
1999	6962
2000	7672
2001	7633
2002	7948
2003	7748