Year	U.S. dollars (Units)
1980	11257.795
1981	10990.447
1982	11036.936
1983	10545.058
1984	10889.934
1985	11488.754
1986	14998.341
1987	18632.076
1988	22122.560
1989	24040.639
1990	28489.569
1991	25646.579
1992	22496.237
1993	17661.586
1994	20429.387
1995	26347.514
1996	25833.030
1997	24759.979
1998	26074.066
1999	26241.797
2000	24379.783
2001	25001.180
2002	27008.262
2003	32961.920
2004	37816.081
2005	39147.216
2006	41308.623
2007	48590.198
2008	53897.910
2009	47541.746
2010	46647.002
2011	51263.574
2012	47850.555
2013	50006.019
2014	50434.791
2015	42867.090
2016	43865.756
2017	46437.211
2018	50032.020
2019	48667.723
2020	49168.162
2021	53610.157
2022	50846.600
2023	54007.975
2024	55126.995
2025	56931.463
2026	58889.344
2027	61015.110
2028	63230.003
2029	65393.703