Year	US Dollars
1960	12.35381
1961	22.14623
1962	16.37417
1963	19.28489
1964	16.19122
1965	20.39808
1966	18.21071
1967	19.20506
1968	15.01775
1969	23.54551
1970	22.35803
1971	20.53824
1972	21.3058
1973	24.53305
1974	31.03624
1975	37.14114
1976	36.73863
1977	40.55299
1978	49.64127
1979	32.70632
1980	36.55736
1981	36.011
1982	29.98281
1983	28.5929
1984	24.19236
1985	21.45773
1986	28.6965
1987	34.82976
1988	39.01825
1989	33.89978
1990	46.50935
1991	41.10704
1992	44.07705
1993	27.09093
1994	11.57042
1995	8.1116
1996	13.45203
1997	20.42489
1998	15.59964
1999	25.89173
2000	22.5243
2001	36.63987
2002	21.5314
2003	29.59349
2004	32.42156
2005	35.45801
2006	41.67001
2007	30.85802
2008	35.46316
2009	45.77772
2010	50.49535
2011	83.86382
2012	91.47082
2013	63.24266
2014	80.73359
2015	42.90357
2016	55.35157
2017	68.73758
2018	67.61059
2019	81.25691
2020	80.16381
2021	89.16292