Year	constant 2015 US$
1960	341130000
1961	259310000
1962	199420000
1963	244100000
1964	205580000
1965	182250000
1966	144650000
1967	130500000
1968	144020000
1969	140140000
1970	172890000
1971	129210000
1972	115720000
1973	169800000
1974	181050000
1975	233190000
1976	302280000
1977	399440000
1978	243630000
1979	199070000
1980	155420000
1981	245100000
1982	142090000
1983	162930000
1984	70800000
1985	127460000
1986	81380000
1987	70440000
1988	68030000
1989	58970000
1990	65600000
1991	88600000
1992	42060000
1993	103620000
1994	165860000
1995	100420000
1996	215850000
1997	158130000
1998	81850000
1999	79020000
2000	127380000
2001	197230000
2002	91810000