Year	US Dollars
1960	13.2345
1961	15.9362
1962	13.75586
1963	9.90812
1964	7.97224
1965	10.75042
1966	13.07217
1967	16.81322
1968	22.10277
1969	26.00877
1970	24.07619
1971	23.0143
1972	17.25776
1973	11.08424
1974	16.45653
1975	13.54632
1976	29.23484
1977	15.24867
1978	33.93143
1979	38.07706
1980	34.24675
1981	66.64221
1982	31.38632
1983	19.54079
1984	12.61587
1985	13.87395
1986	31.35947
1987	30.98051
1988	29.99539
1989	52.58355
1990	220.54139
1991	171.68484
1992	90.57743
1993	117.7346
1994	90.855
1995	90.58267
1996	117.83893
1997	311.8731
1998	99.61715
1999	73.37595
2000	83.82836
2001	84.1264
2002	62.15779
2003	77.94236
2004	133.26775
2005	133.41951
2006	170.77483
2007	103.2093
2008	159.63668
2009	148.05833
2010	142.2723
2011	141.9185
2012	154.46942
2013	135.45262
2014	213.82878
2015	42.56779
2016	92.24239
2017	66.98967
2018	132.62654
2019	139.61762
2020	65.20305
2021	172.52758