Year	US Dollars
1960	5.86366
1961	4.97026
1962	5.09731
1963	6.38027
1964	6.71037
1965	8.38492
1966	13.45674
1967	11.7253
1968	11.19932
1969	11.32147
1970	10.39404
1971	10.81586
1972	13.08932
1973	10.63235
1974	15.36819
1975	8.24341
1976	4.84536
1977	5.98869
1978	8.2256
1979	7.32394
1980	5.09909
1981	4.97509
1982	4.45785
1983	2.61719
1984	2.60483
1985	2.52711
1986	3.11657
1987	2.03015
1988	2.56287
1989	1.9025
1990	2.6983
1991	3.3251
1992	8.11334
1993	3.50973
1994	12.35099
1995	10.54771
1996	12.14601
1997	11.20176
1998	13.62222
1999	15.86957
2000	18.80061
2001	15.73609
2002	13.19618
2003	18.82693
2004	20.14294
2005	20.3685
2006	20.13179
2007	27.68496
2008	27.10964
2009	38.48193
2010	31.68777
2011	37.71402
2012	46.06102
2013	45.26091
2014	46.20592
2015	34.35667
2016	31.20561
2017	25.60259
2018	17.32963
2019	11.36017
2020	12.11367
2021	5.29476