Year	U.S. dollars (Units)
1985	21770.731
1986	14544.374
1987	16561.019
1988	15281.058
1989	16683.224
1990	19428.846
1991	20171.327
1992	20679.723
1993	20430.168
1994	21350.360
1995	24895.613
1996	24460.830
1997	23344.446
1998	17294.914
1999	18237.075
2000	20473.284
2001	18646.040
2002	19037.814
2003	20975.540
2004	24759.511
2005	29459.699
2006	34869.240
2007	36678.272
2008	42529.703
2009	31287.341
2010	35437.251
2011	47092.346
2012	47776.368
2013	44865.244
2014	41947.487
2015	31353.779
2016	27321.997
2017	28443.168
2018	31074.010
2019	29865.278
2020	27174.730
2021	31781.303
2022	37764.306
2023	34248.034
2024	35111.310
2025	36942.888
2026	38541.761
2027	40229.877
2028	42186.422
2029	44549.695