Year	US Dollars
1960	5.08081
1961	9.21475
1962	6.43221
1963	7.42613
1964	7.772
1965	7.96674
1966	7.14852
1967	4.40901
1968	6.39679
1969	5.21813
1970	5.60155
1971	8.45299
1972	6.30852
1973	5.71032
1974	6.78898
1975	15.59047
1976	14.16438
1977	33.26784
1978	22.95842
1979	28.03576
1980	58.99043
1981	51.66699
1982	40.99627
1983	20.98802
1984	15.57344
1985	38.76682
1986	18.74219
1987	18.29
1988	20.37302
1989	20.66912
1990	50.51074
1991	61.33604
1992	37.54231
1993	30.22462
1994	26.08701
1995	18.81872
1996	24.0597
1997	17.21203
1998	19.11389
1999	24.20201
2000	15.66763
2001	17.07046
2002	12.43575
2003	19.70212
2004	25.9913
2005	24.07474
2006	35.72566
2007	39.03705
2008	45.94153
2009	32.64251
2010	30.35589
2011	43.77137
2012	44.10928
2013	59.42131
2014	65.4085
2015	43.77912
2016	58.74312
2017	68.33039
2018	22.77697
2019	20.70713
2020	49.83623
2021	26.03314