Year	U.S. dollars (Units)
1980	695.535
1981	615.660
1982	668.550
1983	619.896
1984	631.152
1985	668.921
1986	640.940
1987	683.625
1988	712.146
1989	715.525
1990	723.431
1991	776.711
1992	803.547
1993	793.646
1994	805.183
1995	886.368
1996	956.965
1997	1006.102
1998	1057.720
1999	1010.580
2000	994.617
2001	949.383
2002	904.851
2003	908.203
2004	968.545
2005	1037.176
2006	1226.845
2007	1383.894
2008	1729.369
2009	1769.441
2010	1972.684
2011	2368.523
2012	2635.933
2013	2938.421
2014	3114.966
2015	3069.319
2016	3110.874
2017	3388.523
2018	3588.089
2019	3591.403
2020	3172.556
2021	3449.384
2022	3705.266
2023	3831.281
2024	4014.178
2025	4218.490
2026	4412.397
2027	4616.964
2028	4830.857
2029	5054.511