Year	US Dollars adjusted for inflation)
1970	5318
1971	5886
1972	6186
1973	6263
1974	5246
1975	4626
1976	5630
1977	6599
1978	7229
1979	7762
1980	8289
1981	8570
1982	8971
1983	9460
1984	9936
1985	10370
1986	10810
1987	11740
1988	12930
1989	13600
1990	14630
1991	14630
1992	15420
1993	15150
1994	15800
1995	17300
1996	17630
1997	18130
1998	18870
1999	19840
2000	20460
2001	21400
2002	21650
2003	22010
2004	22380