Year	U.S. dollars (Units)
1980	412.508
1981	464.914
1982	534.906
1983	560.243
1984	646.388
1985	737.780
1986	835.636
1987	769.824
1988	897.934
1989	987.814
1990	1091.550
1991	1184.664
1992	1343.012
1993	1479.446
1994	1591.140
1995	1903.127
1996	2107.605
1997	2553.949
1998	2658.803
1999	2842.658
2000	2967.253
2001	2780.451
2002	2952.215
2003	3690.792
2004	4238.041
2005	3960.430
2006	5268.793
2007	6128.480
2008	7337.951
2009	7450.805
2010	8086.697
2011	8078.305
2012	8719.582
2013	9766.235
2014	10787.471
2015	11781.029
2016	12348.712
2017	13200.955
2018	14479.839
2019	15060.822
2020	9892.116
2021	14029.908
2022	15962.494
2023	16822.540
2024	17817.780
2025	19223.199
2026	20255.626
2027	21294.957
2028	22323.376
2029	23401.460