Year	US Dollars
1960	0.01894
1961	0.17537
1962	2.75993
1963	4.94486
1964	15.1243
1965	13.12725
1966	20.27186
1967	14.70689
1968	16.237
1969	12.66505
1970	11.01655
1971	11.92229
1972	15.55269
1973	17.3752
1974	23.93247
1975	34.41984
1976	43.61668
1977	28.2092
1978	45.93617
1979	50.41332
1980	49.829
1981	43.00363
1982	48.09498
1983	54.99907
1984	48.21807
1985	33.46335
1986	50.46443
1987	62.83771
1988	38.43191
1989	39.03109
1990	91.03581
1991	54.33659
1992	45.61758
1993	47.9383
1994	136.31323
1995	46.26029
1996	153.12461
1997	93.44924
1998	22.12677
1999	46.58796
2000	10.25836
2001	22.70673
2002	17.15019
2003	20.22979
2004	32.68688
2005	388.13301
2006	67.73619
2007	29.40099
2008	118.99202
2009	66.703
2010	296.33266
2011	56.98684
2012	29.73103
2013	31.27339
2014	21.4728
2015	17.53421
2016	16.78291
2017	20.14931
2018	26.93776
2019	31.71396
2020	37.75051
2021	33.22077