Year	U.S. dollars (Units)
1980	4286.209
1981	4609.426
1982	4793.655
1983	4913.838
1984	5210.542
1985	4458.090
1986	3946.885
1987	4581.216
1988	7506.638
1989	7678.816
1990	3407.070
1991	336.650
1992	1380.594
1993	758.059
1994	1348.670
1995	2284.824
1996	1494.786
1997	1386.466
1998	1854.468
1999	1689.293
2000	1625.322
2001	1797.392
2002	2090.683
2003	2710.577
2004	3370.382
2005	3869.588
2006	4477.028
2007	5815.474
2008	7161.750
2009	6878.061
2010	6754.230
2011	7872.225
2012	7453.726
2013	7703.869
2014	7925.445
2015	7096.339
2016	7593.706
2017	8409.665
2018	9485.446
2019	9909.937
2020	10165.580
2021	12297.273
2022	14023.892
2023	15854.324
2024	16942.519
2025	18075.632
2026	19156.622
2027	20209.419
2028	21324.537
2029	22446.085