Year	constant 2015 US$
2000	21111.993064516566
2001	20890.523894367216
2002	20823.92163203082
2003	21413.28246426812
2004	21413.30536922316
2005	21390.571573832458
2006	21220.186291707392
2007	21564.53058411414
2008	20958.875108589113
2009	18968.974128419573
2010	19319.57117648136
2011	18650.162884143232
2012	21560.78327133081
2013	21939.424775757725
2014	21774.109201745672
2015	21521.058962921885
2016	21542.586160571896
2017	21594.63540940537
2018	21652.879333654648
2019	21949.255005742172
2020	20976.515418440435
2021	21884.554271192523