Year	constant 2015 US$
1991	15955.002727423609
1992	15823.068873902905
1993	15679.382503597915
1994	14292.182662088471
1995	14164.722942873657
1996	14042.004770457936
1997	13873.413021049226
1998	12690.016139181993
1999	11814.262524662208
2000	11100.206593267912
2001	11297.43357330689
2002	11265.411766374082
2003	11879.975145207178
2004	12831.769028394358
2005	12766.435161354755
2006	12998.46848426319
2007	13560.881719716972
2008	13861.730724185323
2009	14379.254478385556
2010	14618.684215934329
2011	14432.233713520778
2012	13787.853934542358
2013	15092.933794613098
2014	15515.81283624723
2015	16069.385603311399
2016	16159.826940139035
2017	15514.129799051208
2018	14876.561013076007
2019	14665.127997390107
2020	14128.472449419645
2021	14067.944267005023
2022	13651.413953123209