Year	US Dollars
1960	-0.45768
1961	3.24364
1962	2.93507
1963	4.13109
1964	2.37546
1965	2.17774
1966	4.43507
1967	4.92712
1968	5.9137
1969	5.21472
1970	6.37304
1971	4.86326
1972	4.69174
1973	5.7697
1974	3.80079
1975	3.01362
1976	2.83821
1977	1.64663
1978	2.30247
1979	1.54461
1980	1.61444
1981	1.99097
1982	2.25359
1983	1.56085
1984	1.74073
1985	1.79089
1986	1.67623
1987	2.67359
1988	2.55593
1989	2.35441
1990	3.09956
1991	3.94829
1992	7.03349
1993	3.0695
1994	2.60543
1995	5.05281
1996	5.32477
1997	5.11585
1998	4.7256
1999	8.25139
2000	5.16051
2001	10.03869
2002	11.32791
2003	19.87448
2004	12.8704
2005	15.23107
2006	23.4901
2007	17.12834
2008	22.3504
2009	23.904
2010	15.01893
2011	22.37066
2012	16.69309
2013	18.54516
2014	26.22588
2015	28.77606
2016	23.23313
2017	17.58719
2018	36.14164
2019	17.40855
2020	36.69518
2021	37.16882