Year	U.S. dollars (Units)
1980	775.709
1981	931.011
1982	876.128
1983	800.450
1984	812.985
1985	837.601
1986	1142.825
1987	1111.670
1988	922.926
1989	892.384
1990	1050.252
1991	920.765
1992	788.501
1993	1033.020
1994	1058.931
1995	820.593
1996	1050.097
1997	700.969
1998	541.273
1999	568.499
2000	550.516
2001	505.213
2002	552.891
2003	647.954
2004	692.685
2005	809.407
2006	839.546
2007	885.101
2008	1125.875
2009	1173.498
2010	1090.263
2011	1274.447
2012	1262.796
2013	1439.109
2014	1545.253
2015	1335.729
2016	1470.016
2017	1594.356
2018	1851.025
2019	1953.567
2020	2181.870
2021	2370.311
2022	2413.087
2023	2827.812
2024	3167.295
2025	3392.648
2026	3460.340
2027	3678.532
2028	3905.489
2029	4148.766