Year	US Dollars
1960	0.52234
1961	0.2862
1962	0.93391
1963	1.5116
1964	8.45289
1965	8.7917
1966	8.03509
1967	7.15465
1968	7.75373
1969	7.06476
1970	7.22166
1971	6.85334
1972	7.75767
1973	7.22289
1974	8.37567
1975	10.64778
1976	7.71194
1977	7.39218
1978	10.71803
1979	15.77145
1980	25.65331
1981	25.30381
1982	25.35321
1983	18.60147
1984	14.99848
1985	17.93014
1986	29.26025
1987	30.35578
1988	26.41078
1989	30.09777
1990	33.40637
1991	37.16622
1992	28.64138
1993	27.74326
1994	21.44518
1995	21.58822
1996	24.77326
1997	56.68012
1998	31.77969
1999	23.03685
2000	20.00934
2001	22.41397
2002	21.72562
2003	30.76904
2004	68.62832
2005	48.75169
2006	40.53736
2007	45.01038
2008	41.29943
2009	20.57622
2010	21.96442
2011	20.01418
2012	16.04485
2013	21.16663
2014	24.28645
2015	27.26298
2016	24.37383
2017	29.76896
2018	28.12318
2019	26.59741
2020	46.00361
2021	36.24646