Year	US Dollars
1979	0.01739
1980	0.06675
1981	0.47883
1982	0.5189
1983	0.65357
1984	0.76916
1985	0.89316
1986	1.02658
1987	1.27052
1988	1.73935
1989	1.84799
1990	1.78878
1991	1.66735
1992	2.5651
1993	2.71747
1994	2.62812
1995	2.87479
1996	2.18135
1997	1.67537
1998	1.97827
1999	1.9214
2000	1.3852
2001	1.17754
2002	1.18051
2003	1.05678
2004	1.31933
2005	1.37939
2006	0.96758
2007	1.10269
2008	0.98557
2009	0.85738
2010	0.50227
2011	-0.44877
2012	-0.13331
2013	-0.48161
2014	-0.69035
2015	-0.22197
2016	-0.57028
2017	-0.70902
2018	-0.50277
2019	-0.43231
2020	-0.40593
2021	-0.40029