Year	U.S. dollars (Units)
1980	1299.661
1981	1608.463
1982	1636.527
1983	1762.992
1984	1390.886
1985	1154.145
1986	1335.761
1987	1084.695
1988	1392.417
1989	977.835
1990	1185.277
1991	1585.242
1992	1592.055
1993	1580.207
1994	1681.396
1995	1897.134
1996	2008.188
1997	2003.578
1998	1824.648
1999	1706.395
2000	1675.793
2001	1577.681
2002	1312.083
2003	1377.521
2004	1693.886
2005	1857.780
2006	2285.125
2007	2988.684
2008	4054.044
2009	3623.931
2010	4329.690
2011	5301.834
2012	5153.417
2013	5892.846
2014	6065.282
2015	5360.077
2016	5265.061
2017	5608.156
2018	5703.324
2019	5302.239
2020	4885.396
2021	5433.251
2022	5628.472
2023	5806.988
2024	5984.287
2025	6191.214
2026	6537.370
2027	6804.303
2028	7084.542
2029	7377.676