Year	current US$
1970	8571428.57142857
1971	8977986.852319922
1972	10028502.35490052
1973	15282973.811987583
1974	16044479.745830024
1975	51469420.17474186
1976	111358200.47656871
1977	25724637.681159418
1978	34737500.55248619
1979	-7545866.141732283
1980	-4134567.944129808
1981	31008306.404565632
1982	32567889.09879467
1983	-28805938.033830177
1984	11346100.33140226
1985	24539526.163723916
1986	9303341.060266996
1987	48471733.63772905
1988	46722854.63921296
1989	5461183.880037488
1990	5502434.218145954