Year	U.S. dollars (Units)
1980	324.386
1981	341.009
1982	349.707
1983	368.714
1984	372.512
1985	375.020
1986	410.714
1987	480.579
1988	533.528
1989	519.641
1990	552.933
1991	479.493
1992	475.802
1993	505.888
1994	520.485
1995	612.147
1996	638.444
1997	703.669
1998	754.037
1999	769.484
2000	814.755
2001	824.986
2002	873.970
2003	1023.488
2004	1142.130
2005	1310.737
2006	1379.091
2007	1665.902
2008	2079.433
2009	1934.381
2010	2265.468
2011	2728.197
2012	2825.188
2013	2842.474
2014	2760.160
2015	2980.157
2016	3071.344
2017	3344.035
2018	3606.621
2019	3547.477
2020	3469.154
2021	3486.101
2022	3775.341
2023	3776.426
2024	4014.386
2025	4340.691
2026	4691.867
2027	4991.436
2028	5319.216
2029	5725.055