Year	U.S. dollars (Units)
1990	652.915
1991	615.663
1992	521.905
1993	553.126
1994	760.992
1995	1224.938
1996	1560.382
1997	1655.818
1998	1802.587
1999	481.951
2000	554.640
2001	583.187
2002	730.836
2003	780.399
2004	963.236
2005	1221.651
2006	1563.031
2007	1791.823
2008	2197.776
2009	1927.476
2010	2328.425
2011	2543.504
2012	2756.410
2013	2998.068
2014	3222.691
2015	2718.586
2016	2176.001
2017	1968.563
2018	2153.094
2019	2229.854
2020	2083.162
2021	2088.090
2022	2202.456
2023	1687.568
2024	1109.899
2025	1076.518
2026	1065.914
2027	1085.256
2028	1103.454
2029	1120.672