Year	constant 2015 US$
1966	11600000
1967	3870000
1968	5970000
1969	8990000
1970	14910000
1971	27120000
1972	25250000
1973	21460000
1974	15480000
1975	18380000
1976	24250000
1977	18020000
1978	31880000
1979	27170000
1980	30220000
1981	38250000
1982	29240000
1983	40170000
1984	18200000
1985	16470000
1986	7580000
1987	10710000
1988	4610000
1989	3090000
1990	3430000
1991	2700000
1992	-250000
1993	4920000
1994	1260000
1995	-1550000
1996	4770000
1997	5500000
1998	20310000
1999	-2860000
2000	660000
2001	-2170000
2002	4400000
2003	23160000
2004	30210000
2005	-2140000
2006	-1880000
2007	15890000
2008	6110000
2009	9630000
2010	14410000