Year	U.S. dollars (Units)
1980	17666.745
1981	15190.085
1982	12464.023
1983	12234.668
1984	11984.274
1985	12393.783
1986	17950.002
1987	22149.518
1988	24875.488
1989	26226.903
1990	33066.888
1991	35346.490
1992	39061.020
1993	39483.057
1994	43306.887
1995	50705.085
1996	49718.865
1997	44202.559
1998	45636.553
1999	49341.225
2000	48984.173
2001	48719.314
2002	53227.765
2003	66160.980
2004	77030.646
2005	81728.362
2006	91478.339
2007	108344.137
2008	121616.145
2009	110249.419
2010	112049.150
2011	120526.246
2012	113953.737
2013	121422.921
2014	125200.137
2015	106710.273
2016	107948.199
2017	111211.579
2018	117993.371
2019	113860.351
2020	117616.151
2021	134925.351
2022	126598.103
2023	129810.315
2024	131384.164
2025	135804.152
2026	138927.725
2027	142003.486
2028	145060.816
2029	148007.194