Year	US Dollars
1960	41.12852
1961	34.01309
1962	26.03582
1963	18.38332
1964	8.55737
1965	10.48036
1966	2.6182
1967	2.24631
1968	1.5179
1969	5.87292
1970	9.14476
1971	9.27976
1972	11.27204
1973	12.4173
1974	32.76363
1975	48.29592
1976	86.51991
1977	144.74097
1978	71.70451
1979	44.53471
1980	77.54734
1981	63.75424
1982	44.35335
1983	26.2482
1984	23.37156
1985	50.37832
1986	47.05116
1987	54.72695
1988	57.68438
1989	52.39252
1990	48.73811
1991	49.7584
1992	32.29146
1993	40.92079
1994	52.14082
1995	24.84874
1996	25.6574