Year	U.S. dollars (Units)
1980	5004.992
1981	5672.105
1982	6000.032
1983	6717.837
1984	7160.262
1985	6788.387
1986	6870.769
1987	7794.688
1988	9328.951
1989	10725.743
1990	12763.342
1991	14501.960
1992	16136.244
1993	18290.132
1994	21552.408
1995	24914.851
1996	26232.869
1997	26375.868
1998	21829.278
1999	21796.642
2000	23852.834
2001	21699.748
2002	22159.833
2003	23730.379
2004	27608.075
2005	29961.308
2006	33768.446
2007	39432.895
2008	40008.577
2009	38926.813
2010	47236.672
2011	53891.462
2012	55547.546
2013	56967.426
2014	57564.802
2015	55645.607
2016	56899.903
2017	61162.097
2018	66840.654
2019	66081.704
2020	61466.819
2021	79601.393
2022	88428.724
2023	84734.277
2024	88446.924
2025	91685.215
2026	95271.736
2027	98816.020
2028	102460.237
2029	106420.978