Year	U.S. dollars (Units)
1980	11009.307
1981	12530.468
1982	12236.781
1983	11593.889
1984	12577.140
1985	10969.385
1986	11247.057
1987	13000.737
1988	16248.647
1989	18206.380
1990	18874.398
1991	18669.073
1992	18117.087
1993	17455.632
1994	19748.800
1995	20921.817
1996	23172.288
1997	23036.829
1998	20394.935
1999	21780.066
2000	20910.760
2001	19498.339
2002	21702.460
2003	27303.124
2004	32871.417
2005	36256.077
2006	37976.196
2007	45205.282
2008	49205.307
2009	45778.860
2010	56591.468
2011	67288.507
2012	68485.597
2013	65250.621
2014	61658.696
2015	51471.651
2016	51829.835
2017	55842.751
2018	56434.012
2019	54395.694
2020	53252.586
2021	64327.187
2022	65574.862
2023	65434.328
2024	66589.055
2025	68613.946
2026	70750.809
2027	72808.266
2028	75319.725
2029	78151.369