Year	U.S. dollars (Units)
1980	673.239
1981	736.992
1982	741.946
1983	659.474
1984	672.201
1985	658.217
1986	610.234
1987	562.902
1988	621.934
1989	696.874
1990	770.757
1991	847.573
1992	907.767
1993	1013.057
1994	1115.613
1995	1254.023
1996	1394.497
1997	1308.114
1998	572.090
1999	829.574
2000	870.154
2001	834.139
2002	1002.907
2003	1186.465
2004	1279.721
2005	1404.348
2006	1765.794
2007	2064.003
2008	2416.785
2009	2469.384
2010	3177.453
2011	3690.097
2012	3739.917
2013	3667.435
2014	3532.669
2015	3368.134
2016	3604.990
2017	3885.967
2018	3945.583
2019	4192.768
2020	3919.465
2021	4358.187
2022	4799.100
2023	4942.361
2024	5270.975
2025	5713.854
2026	6130.674
2027	6565.312
2028	7029.755
2029	7519.119