Year	constant 2015 US$
1960	952770000
1961	924810000
1962	861810000
1963	908470000
1964	763540000
1965	938110000
1966	805230000
1967	513130000
1968	432460000
1969	373710000
1970	366160000
1971	389670000
1972	407990000
1973	776030000
1974	444930000
1975	1645750000
1976	2160020000
1977	2518700000
1978	2630510000
1979	3222460000
1980	2179920000
1981	1773710000
1982	1873730000
1983	2817820000
1984	2562060000
1985	3874470000
1986	3697920000
1987	2314500000
1988	2218490000
1989	2059320000
1990	2264130000
1991	2691600000
1992	3201250000
1993	1947670000
1994	1878100000
1995	496120000
1996	3236380000