Year	US Dollars adjusted for inflation)
1970	2297
1971	2279
1972	2234
1973	2881
1974	3245
1975	3150
1976	3067
1977	3047
1978	3123
1979	3094
1980	2785
1981	2960
1982	3011
1983	3300
1984	3261
1985	3422
1986	3516
1987	3423
1988	3501
1989	3402
1990	3425
1991	3537
1992	3569
1993	3717
1994	4227
1995	4275
1996	4038
1997	3775
1998	3735
1999	3466
2000	3782
2001	3794
2002	3823
2003	3854