Year	constant 2015 US$
1966	114130000
1967	74880000
1968	98230000
1969	100310000
1970	140620000
1971	220840000
1972	272140000
1973	301870000
1974	242350000
1975	198040000
1976	143250000
1977	228470000
1978	281910000
1979	311140000
1980	368300000
1981	323020000
1982	366580000
1983	444670000
1984	341920000
1985	370950000
1986	387080000
1987	448040000
1988	397420000
1989	444490000
1990	397230000
1991	412220000
1992	437100000
1993	507120000
1994	509810000
1995	500890000
1996	444490000
1997	429640000
1998	429760000
1999	415740000
2000	526560000
2001	446230000
2002	457440000
2003	524940000
2004	542690000