Year	constant 2015 US$
1991	15922.564279076021
1992	15147.94752676194
1993	14812.972330161132
1994	13928.221869158418
1995	14036.56305288203
1996	13890.189619839455
1997	13958.745827826498
1998	14122.862708118471
1999	14253.7770076724
2000	14658.638359007777
2001	15433.370703353998
2002	16018.973177201919
2003	17074.66651774143
2004	18155.498574549678
2005	19035.58843691269
2006	18855.21097526631
2007	17628.437079134233
2008	17985.933541039016
2009	17754.02315910552
2010	17866.474840685583
2011	17998.543667697737
2012	18587.661773439493
2013	18326.92248934899
2014	16814.771369115366
2015	15249.644583071264
2016	14587.462707795848
2017	14396.648183954343
2018	14714.305070177077
2019	14131.189614531215
2020	13456.797841205786
2021	14372.468260055446
2022	14009.459285897297