Year	U.S. dollars (Units)
1980	9671.891
1981	10586.565
1982	9782.384
1983	10655.278
1984	11210.553
1985	11813.077
1986	17457.128
1987	21148.433
1988	25506.196
1989	25274.391
1990	25809.747
1991	29436.976
1992	32007.810
1993	36362.624
1994	39953.203
1995	44210.234
1996	39164.322
1997	35651.270
1998	32436.929
1999	36622.892
2000	39172.971
2001	34410.680
2002	32832.296
2003	35410.229
2004	38307.103
2005	37819.107
2006	36021.900
2007	35847.232
2008	39992.060
2009	41469.773
2010	45135.796
2011	48760.915
2012	49175.035
2013	40934.756
2014	38522.771
2015	35005.662
2016	39411.424
2017	38903.298
2018	39850.331
2019	40547.967
2020	40171.929
2021	40114.287
2022	34004.657
2023	33805.939
2024	33138.163
2025	34921.551
2026	36642.656
2027	38064.804
2028	39819.642
2029	40948.610