Year	US Dollars
1972	15850
1973	20160
1974	24700
1975	28350
1976	29870
1977	32490
1978	36450
1979	44230
1980	52790
1981	52490
1982	47410
1983	40860
1984	38120
1985	37590
1986	43380
1987	55320
1988	71200
1989	75280
1990	79560
1991	82530
1992	91310
1993	89570
1994	92220
1995	97050
1996	101120
1997	99630
1998	95020
1999	92430
2000	90830
2001	86420
2002	84090
2003	94220
2004	113130
2005	128440
2006	137370
2007	161010
2008	186080