Year	US Dollars adjusted for inflation)
1970	21620
1971	22200
1972	22500
1973	22710
1974	22840
1975	24690
1976	26240
1977	26480
1978	27070
1979	28950
1980	29970
1981	28520
1982	29170
1983	29340
1984	29240
1985	30390
1986	31150
1987	32390
1988	32870
1989	32680
1990	31620
1991	31120
1992	30170
1993	30970
1994	31270
1995	32160
1996	33010
1997	33670
1998	34200
1999	36490
2000	34030
2001	33600
2002	33960
2003	35750