Year	U.S. dollars (Units)
1980	27242.483
1981	27819.566
1982	22657.373
1983	18003.756
1984	17496.536
1985	15495.701
1986	11644.458
1987	11773.230
1988	10853.896
1989	11039.938
1990	13150.172
1991	11500.519
1992	13038.976
1993	11797.162
1994	12009.396
1995	13689.653
1996	15143.479
1997	18841.600
1998	15421.783
1999	19689.651
2000	30461.311
2001	28600.029
2002	30701.131
2003	35919.758
2004	42548.115
2005	54357.783
2006	60591.776
2007	65934.266
2008	72484.634
2009	53822.909
2010	69796.138
2011	96827.857
2012	101933.117
2013	99180.390
2014	93054.141
2015	66346.911
2016	57965.377
2017	59127.513
2018	66421.617
2019	63007.696
2020	50962.499
2021	65400.854
2022	80572.587
2023	78696.207
2024	81399.515
2025	83381.717
2026	88598.208
2027	94837.145
2028	98586.983
2029	101321.439