Year	U.S. dollars (Units)
1980	7257.484
1981	7514.061
1982	7381.334
1983	7074.640
1984	6970.851
1985	6953.640
1986	8385.754
1987	11205.850
1988	13663.589
1989	13078.997
1990	13447.633
1991	12424.802
1992	11751.977
1993	12537.731
1994	14612.424
1995	16932.664
1996	18506.444
1997	18206.151
1998	14889.751
1999	15348.777
2000	14021.862
2001	13669.348
2002	15706.697
2003	20460.331
2004	24848.791
2005	27385.506
2006	26219.918
2007	31914.298
2008	31762.876
2009	28270.425
2010	33393.032
2011	38061.507
2012	39683.612
2013	42081.344
2014	44284.679
2015	38224.631
2016	39415.045
2017	42289.966
2018	42757.124
2019	42274.230
2020	41341.080
2021	48861.454
2022	47284.147
2023	47536.739
2024	48530.814
2025	49644.841
2026	51049.101
2027	52395.131
2028	54052.205
2029	55738.463