Year	U.S. dollars (Units)
1980	370.185
1981	463.692
1982	516.549
1983	570.682
1984	388.702
1985	559.368
1986	534.912
1987	444.504
1988	406.033
1989	478.384
1990	571.817
1991	787.213
1992	843.597
1993	636.881
1994	344.118
1995	725.815
1996	676.103
1997	628.438
1998	517.661
1999	496.411
2000	327.943
2001	338.362
2002	374.500
2003	435.072
2004	447.804
2005	482.181
2006	467.998
2007	543.408
2008	672.251
2009	613.569
2010	644.344
2011	775.206
2012	688.497
2013	711.927
2014	712.826
2015	707.897
2016	748.089
2017	864.141
2018	894.667
2019	836.954
2020	838.847
2021	930.098
2022	905.854
2023	1016.816
2024	1087.487
2025	1149.592
2026	1213.430
2027	1281.470
2028	1347.568
2029	1408.706