Year	US Dollars
1972	0.02498
1983	0.00968
1985	4.82022
1986	12.92566
1987	14.18361
1988	18.31203
1989	45.41679
1990	87.37695
1991	127.47092
1992	97.38063
1993	101.0376
1994	87.97208
1995	118.58325
1996	112.67428
1997	97.5407
1998	104.16757
1999	100.45117
2000	83.7813
2001	58.99046
2002	71.49495
2003	77.46584
2004	90.40397
2005	57.7625
2006	75.17022
2007	109.79413
2008	100.80194
2009	160.12716
2010	124.48607
2011	130.47168
2012	116.46759
2013	118.41181
2014	100.85595
2015	62.3734
2016	73.25192
2017	80.54441
2018	66.30142
2019	58.9624
2020	72.38767
2021	71.99965