Year	US Dollars
1960	24.60406
1961	32.41059
1962	18.80522
1963	17.56299
1964	33.68284
1965	39.19478
1966	26.5506
1967	23.33768
1968	18.76905
1969	22.69534
1970	13.54815
1971	4.52834
1972	18.63054
1973	21.74058
1974	28.95128
1975	28.37882
1976	25.25421
1977	50.652
1978	77.5566
1979	83.70015
1980	80.42582
1981	57.13961
1982	41.54852
1983	49.39703
1984	42.71353
1985	34.12585
1986	45.10032
1987	57.38998
1988	48.17266
1989	35.91008
1990	62.79779
1991	59.47992
1992	60.54055
1993	56.85662
1994	60.58274
1995	60.5617
1996	33.94663
1997	28.70599
1998	34.7806
1999	28.62417
2000	12.74144
2001	27.99127
2002	21.08851
2003	32.29136
2004	20.56741
2005	43.57739
2006	32.27138
2007	46.7432
2008	64.23702
2009	50.93681
2010	82.86057
2011	112.26095
2012	80.63384
2013	105.32773
2014	76.71435
2015	81.68891
2016	129.22267
2017	128.20157
2018	104.53901
2019	60.302
2020	88.92521
2021	104.87549