Year	U.S. dollars (Units)
1980	338.660
1981	287.809
1982	261.617
1983	233.140
1984	203.120
1985	218.830
1986	279.032
1987	315.981
1988	339.602
1989	330.706
1990	381.987
1991	376.497
1992	393.316
1993	365.700
1994	214.467
1995	258.491
1996	273.892
1997	252.618
1998	281.638
1999	293.779
2000	249.180
2001	260.445
2002	286.551
2003	363.727
2004	405.267
2005	443.189
2006	457.366
2007	516.811
2008	621.822
2009	603.222
2010	627.783
2011	727.484
2012	734.438
2013	762.315
2014	767.569
2015	632.191
2016	665.575
2017	710.541
2018	780.482
2019	765.132
2020	824.248
2021	887.527
2022	830.449
2023	870.833
2024	910.210
2025	952.383
2026	992.331
2027	1033.073
2028	1076.211
2029	1120.340