Year	U.S. dollars (Units)
1997	2417.326
1998	1895.421
1999	1587.882
2000	1302.459
2001	1733.695
2002	2291.259
2003	3009.723
2004	3486.086
2005	3695.343
2006	4398.828
2007	5878.873
2008	7087.453
2009	6168.228
2010	5673.620
2011	6809.940
2012	6014.914
2013	6752.796
2014	6598.935
2015	5588.979
2016	5765.203
2017	6292.546
2018	7252.404
2019	7417.206
2020	7733.803
2021	9186.968
2022	9537.684
2023	11327.130
2024	12383.904
2025	13324.370
2026	14372.028
2027	15446.766
2028	16570.011
2029	17823.626