Year	constant 2015 US$
1997	48795.34863120511
1998	51629.37129965701
1999	55433.6490985411
2000	55756.96228667322
2001	57764.65946841211
2002	56630.71593724013
2003	57524.163055276746
2004	59123.788595477854
2005	59705.922637421776
2006	61059.4768860734
2007	64511.07422099008
2008	63502.12675181311
2009	56289.85687292172
2010	52284.54438001159
2011	46628.68470022872
2012	42510.57547543489
2013	41983.42946741638
2014	41558.69881888365
2015	42281.81125492635
2016	42935.41733551225
2017	42765.69981584842
2018	43277.50141491229
2019	44143.04564147256
2020	41415.666963322146
2021	45269.47404894813