Year	U.S. dollars (Units)
1980	306.980
1981	288.491
1982	279.971
1983	296.509
1984	301.111
1985	292.990
1986	279.908
1987	299.842
1988	368.079
1989	406.534
1990	346.873
1991	356.759
1992	420.025
1993	520.966
1994	468.658
1995	603.526
1996	703.060
1997	774.910
1998	820.903
1999	865.236
2000	951.163
2001	1044.958
2002	1141.140
2003	1282.210
2004	1499.712
2005	1751.368
2006	2095.239
2007	2691.048
2008	3446.695
2009	3813.408
2010	4499.803
2011	5553.242
2012	6282.709
2013	7039.574
2014	7645.875
2015	8034.287
2016	8063.446
2017	8760.259
2018	9848.949
2019	10170.061
2020	10525.001
2021	12572.071
2022	12642.847
2023	12513.871
2024	13136.482
2025	14037.338
2026	14928.761
2027	15833.571
2028	16781.705
2029	17704.741