Year	U.S. dollars (Units)
1980	3489.497
1981	5537.473
1982	6271.521
1983	4114.248
1984	1391.717
1985	1213.391
1986	1094.395
1987	895.180
1988	930.230
1989	924.067
1990	1045.595
1991	1142.797
1992	1102.843
1993	881.079
1994	793.796
1995	918.741
1996	950.015
1997	945.584
1998	1002.604
1999	1012.277
2000	606.501
2001	630.698
2002	714.420
2003	860.469
2004	973.287
2005	1151.305
2006	1320.283
2007	1520.642
2008	1688.077
2009	1477.649
2010	1757.045
2011	2131.746
2012	2197.908
2013	2405.768
2014	2003.714
2015	1784.248
2016	1982.239
2017	2086.598
2018	2275.772
2019	2265.715
2020	2274.572
2021	2535.468
2022	2251.822
2023	2318.309
2024	2229.904
2025	2196.736
2026	2284.684
2027	2375.348
2028	2471.209
2029	2574.451