Year	constant 2015 US$
1963	-140000
1966	70000
1967	70000
1969	250000
1970	370000
1971	550000
1972	990000
1973	1310000
1974	2000000
1975	2670000
1976	4110000
1977	2560000
1978	340000
1979	380000
1980	1110000
1981	1860000
1982	1990000
1983	2470000
1984	3260000
1985	4400000
1986	4140000
1987	4280000
1988	2630000
1989	6870000
1990	3990000
1991	3740000
1992	3550000
1993	4790000
1994	3700000
1995	3890000