Year	constant 2010 US$
1991	18361.0836337569
1992	18227.4018046135
1993	18102.0978977013
1994	17796.0785349827
1995	17593.0296447794
1996	17584.140829625
1997	17674.9432333399
1998	17462.5557606139
1999	17419.9915117976
2000	17525.0146587905
2001	17081.2064865471
2002	16829.1691739263
2003	16560.9941619356
2004	16851.1882438582
2005	17115.5213532566
2006	17350.5384496439
2007	17852.323304926
2008	18133.8884739324
2009	17805.175830448
2010	18366.3811372619
2011	18746.5293827602
2012	18665.4848648826
2013	18824.4128454103
2014	18826.8850282713
2015	18479.2558317422
2016	18394.3671105268
2017	18347.753930444
2018	18405.5039827828