Year	2007 US$
1973	49290000
1974	30650000
1975	50120000
1976	34630000
1977	43250000
1978	93050000
1979	73030000
1980	216800000
1981	157200000
1982	263200000
1983	221000000
1984	307100000
1985	471500000
1986	458100000
1988	347000000
1989	674200000
1990	553000000
1991	670000000
1992	370100000
1993	267000000
1994	186300000
1995	172100000
1996	178500000
1997	213800000
1998	260600000
1999	200500000
2000	220300000
2001	333500000
2002	356800000
2003	361400000
2004	345200000
2005	555100000
2006	443000000
2007	378600000