Year	constant 2015 US$
1960	610000
1961	3160000
1962	2830000
1963	1130000
1964	1380000
1966	2770000
1967	118620000
1974	8290000
1975	10030000
1976	11420000
1977	8160000
1978	3760000
1979	4430000
1980	9490000
1981	8010000
1982	8330000
1983	7370000
1984	4530000
1985	5060000
1986	2960000
1987	3630000
1988	3030000
1989	8980000
1990	7630000
1991	7880000
1992	6890000
1993	4560000
1994	14800000
1995	1700000
1996	1500000
1997	2250000
1998	1310000
1999	2980000