Year	constant 2015 US$
1991	17145.865065417314
1992	17250.95107160215
1993	17282.700565080177
1994	16950.988405653432
1995	16597.6099987457
1996	16717.575134815394
1997	17046.839957254735
1998	17011.596311154797
1999	17055.55053846937
2000	17216.817262429337
2001	16869.989516919522
2002	16675.91818999631
2003	16375.549463137753
2004	16603.659428289877
2005	16719.345039101256
2006	16939.19394285139
2007	17408.471796282436
2008	17658.0024214107
2009	17249.214671776088
2010	17886.785819127752
2011	18279.54477740826
2012	18288.125484389155
2013	18476.315626370142
2014	18491.338689572898
2015	18343.968965149197
2016	18261.25334459881
2017	18278.695782258383
2018	18267.28592572763
2019	17981.95407703816
2020	18308.950625669444
2021	18370.85147507816
2022	18107.31518599079