Year	current US$
1987	10270131537.3864
1988	10831062669.8544
1989	11107822675.0741
1990	9905594943.63756
1991	7133693312.64895
1992	6081430622.0393
1993	6490536958.40596
1994	7464476170.70527
1995	9394489025.93477
1996	9626733092.55318
1997	8515658394.60785
1998	9058060866.27165
1999	7686092423.65354
2000	7491372292.27841
2001	8089219263.45996
2002	10298256912.1308
2003	12158408394.0468
2004	14209043985.9348
2005	17757827491.8846
2006	20505494048.2531
2007	26537347824.397
2008	31181841995.1075
2009	28404573265.6603
2010	29583947089.3029
2011	35689557544.9128
2012	32917465214.4621
2013	34880718454.344
2014	36922845204.2791
2015	32068457240.8972
2016	33595105588.8086
2017	36535673199.2903
2018	42068259022.6674
2019	42332079151.4372
2020	38799338431.9118
2021	44011441588.4566