Year	US Dollars
1960	2.11429
1961	5.44096
1962	7.55721
1963	6.97038
1964	6.78482
1965	11.03206
1966	14.12415
1967	14.99582
1968	13.83013
1969	13.22996
1970	9.50677
1971	15.63386
1972	12.61344
1973	12.26631
1974	17.54343
1975	23.41759
1976	22.69837
1977	28.32896
1978	37.11652
1979	47.27094
1980	66.18019
1981	71.32983
1982	62.04653
1983	69.38368
1984	62.58315
1985	57.01749
1986	51.44015
1987	61.71499
1988	62.81244
1989	76.11945
1990	77.33754
1991	67.4006
1992	77.02957
1993	75.87466
1994	60.51369
1995	58.24478
1996	52.79019
1997	46.3809
1998	31.14866
1999	15.88071
2000	18.59774
2001	27.78232
2002	38.54753
2003	39.70336
2004	48.00583
2005	34.61069
2006	36.01311
2007	65.99562
2008	72.53584
2009	60.856
2010	126.58528
2011	126.01113
2012	134.45155
2013	154.61883
2014	51.14922
2015	40.82565
2016	52.27458
2017	67.10535
2018	69.95396
2019	63.00035
2020	75.70205
2021	77.67853