Year	constant 2015 US$
1991	3174.881709179
1992	3269.6110634393804
1993	3598.8090418775805
1994	3889.612428431496
1995	4137.568161283375
1996	4377.3682811623785
1997	3983.8263400113024
1998	3908.560974329038
1999	4077.390991275669
2000	3493.938773621413
2001	3717.252191711423
2002	3538.1975819277677
2003	3722.860785066935
2004	3556.279969202816
2005	3313.11859093525
2006	3900.0288784096606
2007	3674.8744590565598
2008	3442.071264767758
2009	3996.6320283596924
2010	4039.7097377991763
2011	4410.774512288953
2012	4362.22814025338
2013	4208.9888894928645
2014	4004.2997777150154
2015	3925.3833893121064
2016	4694.304224296363
2017	4373.742578949249
2018	4573.88731538416
2019	4734.554487172701
2020	4636.938103291369
2021	4856.960017346658
2022	5408.867190866784