Year	2007 US$
1971	197900000
1972	200600000
1973	140900000
1974	244700000
1975	251100000
1976	231100000
1977	338900000
1978	455000000
1979	388500000
1980	358600000
1981	284500000
1982	822900000
1983	770500000
1984	700600000
1985	934100000
1986	942400000
1987	617200000
1988	877200000
1989	936800000
1990	636200000
1991	726400000
1992	742500000
1993	882800000
1994	825900000
1995	677000000
1996	1253000000
1997	1016000000
1998	454800000
1999	935500000
2000	1219000000
2001	695400000
2002	926200000
2003	882800000
2004	1481000000
2005	1528000000
2006	823400000
2007	946200000