Year	U.S. dollars (Units)
1980	728.359
1981	817.734
1982	824.542
1983	815.529
1984	788.332
1985	788.801
1986	855.724
1987	832.245
1988	805.046
1989	860.784
1990	675.736
1991	408.022
1992	259.750
1993	452.623
1994	736.028
1995	903.989
1996	1009.967
1997	717.381
1998	818.320
1999	1032.264
2000	1127.640
2001	1283.573
2002	1425.125
2003	1846.119
2004	2373.580
2005	2673.773
2006	2972.745
2007	3595.053
2008	4370.562
2009	4114.090
2010	4097.833
2011	4439.890
2012	4248.909
2013	4415.600
2014	4584.919
2015	3953.611
2016	4124.405
2017	4525.887
2018	5257.714
2019	5345.058
2020	5278.986
2021	6259.762
2022	6657.637
2023	7956.559
2024	8924.317
2025	9474.065
2026	10135.055
2027	10827.923
2028	11578.584
2029	12389.740