Year	constant 2015 US$
1990	17322.6917241398
1991	19091.463647457607
1992	18960.351381481836
1993	17602.298004067525
1994	16175.743709195356
1995	15391.988520819183
1996	20441.89430255259
1997	16473.757970592287
1998	15047.235260274043
1999	15526.276993401225
2000	15832.377838552859
2001	16104.76463507457
2002	17670.10143170975
2003	17686.069189539852
2004	19468.156918472847
2005	21728.97353733973
2006	23391.380453751724
2007	24011.23659602801
2008	29525.566309545542
2009	24305.82672407867
2010	24439.543488436902
2011	28023.867316600867
2012	29655.81225901538
2013	29332.610075880468
2014	28397.621236587
2015	25264.398318713116
2016	24004.08508711291
2017	24816.75991819774
2018	24037.84733434973
2019	24766.061449227775
2020	22716.552639889014
2021	22912.291073416643