Year	2007 US$
1967	15890000
1968	77440000
1969	273200000
1970	154400000
1971	577900000
1972	946800000
1973	600000000
1974	1371000000
1975	1490000000
1976	3300000000
1977	2447000000
1978	2507000000
1979	2487000000
1980	2909000000
1981	2282000000
1982	2033000000
1983	1866000000
1984	1791000000
1985	1563000000
1986	2255000000
1987	2277000000
1988	2175000000
1989	2555000000
1990	2306000000
1991	1194000000
1992	2137000000
1993	2114000000
1994	1461000000
1995	1708000000
1996	1696000000
1997	1615000000
1998	1597000000
1999	1202000000
2000	1651000000
2001	2141000000
2002	2775000000
2003	1627000000
2004	2390000000
2005	2625000000
2006	4923000000
2007	2715000000