Year	2007 US$
1968	1090000
1969	191500000
1970	62170000
1971	97820000
1972	71050000
1973	54020000
1974	323900000
1975	41960000
1976	33190000
1977	286900000
1978	312600000
1979	110100000
1980	280700000
1981	711600000
1982	763200000
1983	465400000
1984	211500000
1985	161000000
1986	249200000
1987	238800000
1988	557300000
1989	674800000
1990	340800000
1991	529800000
1992	474400000
1993	571400000
1994	448800000
1995	368200000
1996	270500000
1997	305800000
1998	371800000
1999	509700000
2000	317700000
2001	229500000
2002	328400000
2003	249800000
2004	235600000
2005	281000000
2006	296300000
2007	359700000