Year	constant 2015 US$
1960	760000
1961	8680000
1962	12020000
1963	5640000
1964	4940000
1965	7070000
1966	64880000
1967	380000
1968	1740000
1969	1060000
1970	5910000
1971	26080000
1972	14560000
1973	62620000
1974	148840000
1975	89950000
1976	545160000
1977	148400000
1978	226280000
1979	321730000
1980	453340000
1981	444250000
1982	359370000
1983	589570000
1984	498170000
1985	173350000
1986	191290000
1987	14530000
1988	-4290000
1989	-3680000
1990	193560000
1991	128540000
1992	103050000
1993	146840000
1994	120140000
1995	112420000
1996	157350000
1997	191350000
1998	260130000
1999	79090000
2000	80040000
2001	98820000
2002	82980000
2003	157010000
2004	63820000